July 2007

By Bill Kendig

Photography by Joseph Byrd

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| Wouldn't it be nice to demo every new regulator before committing your hard-earned cash? It is, after all, the most important piece of gear you'll buy, which puts a lot of pressure on making the right decision--and that's where Scuba Lab comes in.

We invited all major manufacturers to submit their new regulators (introduced within the last 12 months) for this review. After inspecting them and reviewing the owners' manuals, we put them on an ANSTI breathing simulator to measure the precise breathing resistance a diver will encounter at four different depth/breathing rate settings that range from normal breathing at 132 feet to extreme exertion at 198 feet. Then we turned the regs over to a team of eight test divers to be your stand-ins. Their mission was to rate each reg using a 1 to 5 scale in seven ergonomic performance categories, from ease of breathing to comfort features. These divers also made notes on each reg--what they liked and what they didn't like. We then polled our test divers to find out which reg in each price category offered the best combination of features, comfort and performance and awarded these regs the additional honor of being named a Scuba Lab Testers' Choice (see "Testers' Choice & Best Buy").

The complete results of all our tests are found in the charts, and are summarized in the following reviews, which are presented here in alphabetical order within price categories.

Regulators Over $500

Apeks: XTX50 Status and XTX200 Status

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| | Apeks: XTX50 Status| |

| | Apeks: XTX200 Status| ProS: Perfect simulator scores; well-designed user adjustments; built-in electronic intermediate pressure gauge; reversible hose configuration.

ConS: High price; large first-stage (XTX50 Status).

First Stage: These are the first regs to feature a built-in electronic intermediate pressure gauge, complete with an LCD screen that indicates if the pressure is "HI," "LO" or "OK" before every dive. The electronics also track the date and hours of use to indicate when it's time for routine service. Beneath the digital brain are two different versions of an over-balanced, environmentally sealed diaphragm first stage that has plenty of brawn. Both regs offer four low-pressure ports and two high-pressure ports for convenient hose routing (low-pressure ports are on a rotating turret on the XTX50; angled on the XTX200). Both regs come factory ready for nitrox mixes up to 40 percent. The XTX50 first stage comes in a bigger, bulkier package, compared to the compact XTX200 first stage. Both are available with a DIN connection.

Second Stage: The pneumatically balanced second stages are identical except for a few cosmetics--the XTX200 has chrome trim, the XTX50 does not. Well-designed adjustments include a large control knob with a wide range of travel for taking breathing resistance right to the edge of cracking effort, and a ratcheting venturi lever that lets you tune out freeflows. Both second stages also feature a reversible hose configuration.

Test Divers Said: The large ratcheting venturi and the adjustment knob are easy to find and use, even with gloves. Many test divers also liked the Comfo-Bite mouthpiece. Clearing was easy and the purge button was effective without blasting fillings loose. Breathing was very dry in all positions, and there was no drop in performance in various positions.

The ANSTI Report: Both regs aced the breathing machine panel with a remarkably stable performance regardless of depth or demand.

Price: $847 for the XTX50 Status; $990 for the XTX200 Status.

Apeks: XTX200 Tungsten Swivel

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| | Apeks: XTX200 Tungsten Swivel| Pros: Perfect simulator scores; well-designed user adjustments; great hose swivel connection on the second stage; cool-looking protective finish.

Con: High price.

First Stage: This compact, environmentally sealed, over-balanced diaphragm first stage is the flagship regulator for Apeks--and it looks really cool to boot. The hardened tungsten PVD finish is not just for show, it also protects the reg from the elements. Four low- and two high-pressure ports are angled for comfortable hose routing and there's a brass plaque affixed to the first stage for a distinct appearance. It's nitrox-ready right out of the box for mixes up to 40 percent and shares the same smooth-breathing performance as the regular XTX200.

Second Stage: The Tungsten finish is also found in the grill of the second-stage cover and on the adjustment knob. It has all the same adjustment features found on the other XTX second stages, plus it comes standard with a great new hose swivel connection that test divers loved.

Test Divers Said: "It felt like the hose wasn't even attached," wrote one test diver commenting on the swivel connection. As with the other XTX second stages reviewed here, the large control lever and adjustment knob were also a hit.

The ANSTI Report: Another perfect score. The addition of the swivel made no significant difference in breathing performance.

Price: $965.

Aqua Lung: Kronos

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| | Aqua Lung: Kronos| Pros: Compact first stage; simplified user adjustments; unique side-venting exhaust tee; ACD dam on first-stage inlet.

Con: Base version we tested is not dry sealed (bummer), but an environmentally sealed version called the Kronos Supreme is available at a higher price ($615).

First Stage: The Kronos balanced-diaphragm first stage offers a full contingent of four low-pressure and two high-pressure ports, giving you more flexibility in hose routing and the option to use both a transmitter and pressure gauge hose. The first-stage opening features Aqua Lung's Auto-Closure Device (ACD), which closes the inlet to water intrusion whenever the reg is off a tank. Another nice touch: The yoke knob is covered with soft rubber for an easier grip with wet hands.

Second Stage: The new Side-X exhaust system on the Kronos pneumatically balanced second stage directs all bubbles to the diver's right for clearer viewing. An added benefit is that warm air passes over the second stage valve and hose, fighting freeze-up in cold water. The new Dual Cam control simplifies adjustment by combining the venturi and breathing resistance knobs into one easy-to-find lever. While the range of adjustment is small, it does the job of stopping freeflows at the surface and fine-tuning breathing performance underwater. The Kronos comes with both a Comfo-Bite mouthpiece and a standard spare.

Test Divers Said: "The Dual Cam lever was glove-friendly and prevented surface freeflows," wrote one test diver, echoing the comments of the others. Our divers also gave the Side-X exhaust system a unanimous thumbs-up. The compact second stage was an easy breather, stayed dry in all positions and was easy to clear.

The ANSTI Report: Work of breathing scores fell into the Excellent category for the test that most closely represents recreational diving and the Very Good category for the more extreme tests. Close inspection of the breathing loops shows that in these high-volume breathing situations and at depths to 198 feet, the reg's inhalation effort was very stable while the exhalation effort increased only slightly as the tests got more challenging.

Price: $569.

Atomic Aquatics: ST1

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| | Atomic Aquatics: ST1| Pros: Lowest overall work of breathing; corrosion resistance at a lower cost than titanium; great second-stage swivel for added comfort.

Con: High price.

First Stage: The ST1 is a balanced-piston first stage turned from 316 stainless steel that offers greater strength and corrosion resistance than brass regulators at a significantly lower cost than titanium. It offers four low-pressure ports on a swivel turret with a fifth port on the end of the first stage for easy hose routing, plus two high-pressure ports.

Second Stage: The ST1 delivers high performance with a dose of comfort thanks to a well-designed mouthpiece and Atomic's Comfort Swivel. It also features all the usual Atomic features--Automatic Flow Control (AFC), a self-adjusting venturi effect that increases breathing performance as you descend; the Rapid Adjustment Knob, which allows the user to de-tune the reg for surf entries or octopus use; a flexible purge cover; and the Seat Saving Orifice, which helps maintain the reg's peak performance over time. Inside the second stage, the entire valve body and lever of this pneumatically balanced second stage is made of corrosion-resistant titanium.

Test Divers Said: Divers thought the ST1 was one of the "smoothest breathing" regulators of the bunch and gave it the highest ergonomic scores of all the regulators in this review. The comfort swivel helped boost comfort scores and test divers had praise for the user control knob and soft purge cover. This reg also received the highest score for Ease of Breathing and was the only reg rated Excellent by test divers for dryness. When we polled our test divers for their top reg in the price category, the ST1 was a clear Testers' Choice (see "Testers' Choice & Best Buy," p. 73).

The ANSTI Report: While several regs in this review earned perfect breathing machine scores on our 1 to 5 scale, the ST1 can boast the lowest overall work of breathing in every one of our ANSTI tests.

Price: $899.

Dive Rite: Hurricane

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| | Dive Rite: Hurricane| Pros: Compact tech-friendly reg; well-machined user adjustments; dry breather in all positions.

Con: Mouthpiece too small for some.

First Stage: The new Hurricane from Dive Rite is a cyclone of air in a small package. The first stage is an over-balanced diaphragm that is cold-water-ready down to 36F, nitrox-compatible up to 40 percent, and comes standard with a DIN connection. Angled ports put hoses where you want them with two high-pressure and four low-pressure fittings. A bright red cap protects the first stage against overhead scrapes and aids in diver recognition.

Second Stage: The pneumatically balanced second stage offers multiple adjustments to fine-tune your dive. A large red venturi control lever puts a stop to surface freeflows and is easy to use with gloves. The breathing resistance knob offers a wide range of adjustment to dial in your preferred flow as you descend. A comfortable mouthpiece and a wide exhaust tee are a nice touch.

Test Divers Said: Breathing adjustments were "smooth and effective," offering "a well-machined feel." Our test divers also said the reg clears easily with a powerful purge action. The wide exhaust tee did a nice job of directing bubbles away, and breathing was dry in all positions. The venturi control lever prevented surface freeflows and opened up nicely underwater. While the mouthpiece is soft and comfortable, it was a little small for many of the testers.

The ANSTI Report: The Hurricane delivered an Excellent performance in the test that most closely replicates recreational diving and Very Good scores in the more extreme tests.

Price: $599.

Regulators Under $500

Mares: Proton 12 Metal

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| | Mares: Proton 12 Metal| Pros: High performance at a reasonable price; new tri-material first-stage valve; proven diver-friendly design.

Con: Narrow exhaust tee allows some bubble interference.

First Stage: The Proton 12 Metal has been one of Mares' best breathing, balanced-diaphragm regulators for years, and it's still going strong. What's new is the "tri-material" first-stage valve, made of brass and two different polyurethane compounds. It's designed to last longer and perform better than previous versions. It also has the Dynamic Flow Control feature, a dedicated low-pressure port that helps deliver big air to your primary second-stage hose for easy breathing.

Second Stage: The Proton Metal is the smallest second stage in this test group, and its solid metal construction makes this reg well suited to cold-water diving. The Vortex Assisted Design (VAD) directs air to the diver through a bypass tube from the valve seat to the mouthpiece. The large front-cover purge is smooth and easy to find, even with gloved hands. The orthodontic mouthpiece is soft and comfortable and the exhaust tee follows the shape of the regulator, but allows greater-than-average bubble interference.

Test Divers Said: It's hard not to like a light, compact and easy-to-use reg. The Proton Metal delivers easy, dry breathing without the need for user adjustments, and the reg is comfortable in the mouth. All test divers commented on the ease and function of the large purge saying it was "smooth and powerful."

The ANSTI Report: The Proton Metal earned Excellent breathing machine scores across the board, another reason this regulator is still going strong.

Price: $450.

OMS: R250 High Performance

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| | OMS: R250 High Performance| Pros: Environmentally sealed and rugged; nice adjustment knob; easy clearing.

Cons: Small mouthpiece, some bubble interference.

First Stage: OMS uses an environmentally sealed balanced-diaphragm first stage that is tech-ready with a DIN connection and nitrox capabilities up to 40 percent. This compact performer provides four low-pressure and two high-pressure ports, angled for easy routing.

Second Stage: The R250 second stage is light and offers user adjustments for venturi and breathing resistance control. The large adjustment knob can dial you right to the edge of freeflow for crisp cracking effort. The Dive/Predive venturi switch is easy to find--on top, just in front of the mouthpiece--but it's smaller than most levers in this test group. The small exhaust tee is streamlined, but didn't wrangle bubbles as well as others tested.

Test Divers Said: Testers said the regulator was easy-breathing and dry in most positions. Some thought the mouthpiece was a little small, but most liked the "huge range of adjustment" the regulator had to offer. Clearing was smooth and easy both by exhaling and purging, though the front purge cover was "a little stiff."

The ANSTI Report: The R250 earned Excellent breathing scores at the first test point. At greater depths and breathing rates the regulator's work of breathing numbers fell into the Good category across the board.

Price: $418.45.

Scubapro: MK11/R395 and MK11/S555

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| | Scubapro: MK11/R395| |

| | Scubapro: MK11/S555| Pros: Excellent performance at a budget price (MK11/R395); compact first stage; nice second-stage adjustment; smooth and dry-breathing in all positions.

Con: Some bubble interference.

First Stage: The MK11 first stage was the smallest of the test group but held its own, putting up some of the best test scores recorded in this review. This over-balanced diaphragm first stage features two high-pressure and four low-pressure ports, two of which are marked "HFP" for pumping out 15 percent greater air flow. Convert to a DIN connection and you have the makings of a compact tech rig. The big surprise is that the MK11/R395 came in with the lowest price ($384) but with some of the highest performance, earning our Best Buy recommendation.

Second Stages: The R395 second stage is light and simple with just the VIVA venturi to adjust. It uses a large control knob in front of the mouthpiece that's clearly marked "Dive/Predive." Inside the case are a new lever and diaphragm that are designed to reduce friction. The low-pressure hose can be configured on either the right or left side to customize your rig and the flexible cover allows for easy purging. The S555 second stage is pneumatically balanced, which translates into lower cracking effort at depth. The case body and valve lever assembly are designed to prevent freeze-up and it has the same excellent dive/predive switch as the R395.

Test Divers Said: Our divers found both regs to be smooth and easy breathers. The easy-to-locate front purge covers were effective. The mouthpiece was comfortable for most while some bubbles interfered with viewing in certain positions. Breathing was affected in certain head-up positions with the R395, but not as much with the balanced S555 second stage. Both regulators breathed dry in all attitudes. Most telling: test divers voted the MK11/S555 their Testers' Choice for regulators under $500.

The ANSTI Report: The breathing machine loved these regulators. Work of breathing was Excellent in all tests, and the regs turned in almost identical results.

Price: $384 for the MK11/R395 and $489 for the MK11/S555.

Specialty Regulator

Apeks: Tek3 XTX50

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| | Apeks: Tek3 XTX50| Pros: Comes in right- and left-side configurations for twin cylinders; environmentally sealed; excellent breathing performance.

Con: Port configuration is not favorable for single-tank diving.

First Stage: The Tek3 first stage is the first regulator designed specifically for twin cylinders, offering one high-pressure port and three low-pressure ports, all on one side. Consequently, the Tek3 is made in right- and left-hand versions. It is available in DIN or yoke configurations and comes nitrox-ready up to 40 percent. It's over-balanced and environmentally sealed for the most demanding conditions.

Second Stage: The XTX50 second stage is pneumatically balanced, with significant user adjustments and offers reversible hose configuration. The resistance adjustment knob is large and offers a wide range for fine-tuning. The indexed venturi control lever lets you ratchet up the flow on descent and block unwanted freeflow on the surface. A wide exhaust tee keeps bubbles out of view and can be exchanged with a smaller one for use as a streamlined octopus.

Test Divers Said: The Tek3 was a smooth breather and dry in all positions. User adjustments are "easy to find and operate."

The ANSTI Report: The Tek3 XTX50 received Excellent scores in all breathing machine tests.

Price: $1,450 for the Tek3 Complete set (left- and right-side Tek3 first stages, two XTX50 second stages, a two-meter hose, a standard hose and a regulator necklace); $925 for a matched pair of Tek3 first stages.

Testers' Choice & Best Buy

Q: What is a Scuba Lab Testers' Choice?

A: We award the Testers' Choice logo to the gear that our team of divers vote as their favorite combination of fit, features and performance based on their extensive in-water use.

Q: How do you determine Testers' Choice ratings?

A:A: While in the past we used a complicated points-based system to determine what gear earned our coveted Testers' Choice rating, for 2007 we simplified the process. At the conclusion of our in-water testing, we divided the regs into their respective price groups and polled our test divers with one final question: "Which one would you buy?" It's fascinating to see the wheels turning as each test diver calculates all the pros and cons and comes up with their individual answers.

Q: Does not earning a Testers' Choice mean gear is substandard?

A:A: Not at all. As you can see from the individual reviews and the charts on p. 98, every regulator tested performed admirably on the breathing machine, and all were able to stand up to the most punishing tests. In the ergonomic evaluations, the lowest score test divers gave any reg in any category was a Good rating. The results of each review stand on their own and should be read carefully and completely. Testers' Choice is merely an additional tool to help you analyze the results and make an informed buying decision.

Q: What is a Scuba Lab Best Buy?

A:A: While Testers' Choice is based on the voting of test divers, Best Buy is awarded at the discretion of the Scuba Lab staff. We award this logo to the gear that we think is a particularly good combination of performance and price.

Regulator Features

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| | Price| $847| $990| $965| $569| $899| $599| | Warranty| Ltd. Lifetime| Ltd. Lifetime| Ltd. Lifetime| Ltd. Lifetime| Ltd. Lifetime| Ltd. Lifetime| | Made In | UK| UK| UK| France| USA| France| | 1st Stage | Over- Balanced Diaphragm| Over- Balanced Diaphragm| Over- Balanced Diaphragm| Balanced Diaphragm| Balanced Piston| Over- Balanced Diaphragm| | Ports| 2 HP 4 LP| 2 HP 4 LP| 2 HP 4 LP| 2 HP 4 LP| 2 HP 5 LP| 2 HP 4 LP| | 2nd Stage | Pneu- matically Balanced| Pneu- matically Balanced| Pneu- matically Balanced| Pneu- matically Balanced| Pneu- matically Balanced| Pneu- matically Balanced| | 2nd Stage Adjustments | Resistance Knob RVS*| Resistance Knob RVS*| Resistance Knob RVS*| Dual- Cam† (venturi/ resistance)| Resistance Knob| Resistance Knob Venturi Lever| | Factory Ready Nitrox Capable | Up to 40%| Up to 40%| Up to 40%| Up to 40%| Up to 40%| Up to 40%| | †Dual Cam (combines venturi control with breathing resistance control) * Reversible Venturi System ** Venturi Initiated Vacuum Assist|

Regulator Features Continued

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| | Price| $450| $418.45| $384| $489| $1,450 (2 complete regs); $925 (LH and RH first stages only)| | Warranty| Ltd. Lifetime| 1 Year| Ltd. Lifetime| Ltd. Lifetime| Ltd. Lifetime| | Made In | Italy| USA| Italy| Italy| UK| | 1st Stage | Balanced Diaphragm| Balanced Diaphragm| Over- Balanced Diaphragm| Over- Balanced Diaphragm| Over- Balanced Diaphragm| | Ports| 2 HP 4 LP| 2 HP 4 LP| 2 HP 4 LP| 2 HP 4 LP| 1 HP 3 LP| | 2nd Stage | Unbalanced| Unbalanced| Unbalanced| Pneu- matically Balanced| Pneu- matically Balanced| | 2nd Stage Adjustments | N/A| Resistance Knob Dive/Pres- Dive Switch| VIVA**| VIVA**| Resistance Knob RVS*| | Factory Ready Nitrox Capable | Up to 40%| Up to 40%| Up to 40%| Up to 40%| Up to 40%| | †Dual Cam (combines venturi control with breathing resistance control) * Reversible Venturi System ** Venturi Initiated Vacuum Assist|

How We Test Regulators

ANSTI Breathing Simulator

The ANSTI machine is the international industry standard for scientifically evaluating a regulator's performance. It measures a regulator's work of breathing (WOB) in joules per liter (j/l) for each complete inhale/exhale cycle. We test regulators at four different RMV/depth combinations (RMV stands for Respiratory Minute Volumes, basically the amount of gas that can be ventilated through the lungs in one minute). All simulator tests are performed at a supply pressure of 725-760 psi. If a regulator can perform well at this supply pressure, it will perform as well or better at higher supply pressures. Here are the tests and what they represent:

Column A 37.5 RMV @ 132 fsw. A somewhat aggressive breathing rate at the maximum recreational diving depth. A physically fit recreational diver might breathe at this rate while swimming a long distance. (A relaxed diver on a drift dive will probably be breathing at 22 RMV or less.) A diver could theoretically maintain 37.5 RMV for five minutes or longer without becoming significantly winded.

Column B 75 RMV @ 132 fsw. An extremely aggressive breathing rate at the maximum recreational diving depth. A diver in excellent condition can breathe at 75 RMV for about one minute. This test represents how a reg might perform with a single diver breathing at an extremely heavy work rate. It also serves as a loose simulation of the stress a reg would be under if two divers were breathing off the same first stage in an air-sharing situation. Only the U.S. Navy and Scuba Lab use this breathing rate to help identify the outer limits of a reg's performance.

Column C 62.5 RMV @ 165 fsw. All regs sold in the European Common Market must pass a test standard known as EN250, which uses this RMV/depth as its benchmark. For this reason, it's also the depth and breathing rate most commonly used by manufacturers to test regulators. This is a very aggressive breathing rate. A recreational diver in excellent condition chasing a bat ray through open water would probably be able to maintain 62.5 RMV for only a few minutes.

Column D 62.5 RMV @ 198 fsw. This is the U.S. Navy's Class A test depth and breathing rate, although we use a lower supply pressure (725-760 psi). We conduct this extreme test (no diver should ever be breathing this aggressively at this great a depth with this little air left in his tank) to explore the outer limits of a reg's performance.

Our test parameters state that the highest inhale or exhalation pressure experienced by the "diver" should never exceed 25 millibars or a total WOB of 3 j/l. If a reg exceeds either parameter, it "fails" our test, but that doesn't mean that it stops delivering air--only that the breathing resistance at some point in the cycle is higher than what is common for most modern regulators.

A machine as accurate as the ANSTI simulator can accurately differentiate j/l measurements to tenths and even hundredths of a point. Human divers, however, can't. For the sake of simplicity, we translate j/l measurements into scores on a 2 to 5 scale as follows:

5=Excellent: A total WOB of 1.05 j/l or less.
4=Very Good: A total WOB of 1.06 to 1.55 j/l.
3=Good: A total WOB from 1.56 to 2.25 j/l.
2=Fair: A total WOB of 2.26 to 3.0 j/l.

Ergonomic Tests: The Human Factor

Breathing machines tell only half the story. To gauge the ergonomic traits of regulators, we use a minimum of six test divers. Each diver rates each reg for user-friendliness in seven areas:

Ease of breathing: How well a regulator delivers air in the standard swimming position.

Different positions: How the regulator breathes when the diver is in a heads-up or face-down position.

Dryness: Does the regulator breathe wet or dry in both a normal swimming position and odd swimming positions?

Bubble interference: Considered while looking down, straight ahead, up at a 45-degree angle and straight up.

Ease of clearing: Divided into two parts: 1) How easy is it to find and use the purge button, and how forceful is the purge? 2) How much force is required to clear the regulator using the blowing method?

Comfort: Test divers rate the comfort of the mouthpiece, the feel of the second stage in the mouth, hose lengths and stiffness.

Adjustments: Are adjustments easy to find, grip and turn? Do they do their job in a reasonable manner?

Performance is recorded using both numeric scores on a 1 to 5 scale (5=Excellent, 4=Very Good, 3=Good, 2=Fair, 1=Poor) and written comments.

Test Diver Ratings Of Ergonomic Performance & ANSTI Breathing Simulator Results

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| | Ease of Breathing | 4| 5| 5| 4| 5| 4| | Different Positions | 4| 4| 4| 3| 4| 4| | Dives Dry | 4| 4| 4| 4| 5| 4| | Bubble Interference | 4| 4| 4| 5| 4| 4| | Clearing Blow/Purge | 4| 4| 4| 4| 4| 4| | Comfort | 4| 4| 4| 4| 4| 4| | Adjustments | 4| 4| 4| 4| 4| 4| | ANSTI Breathing Simulator Results| | A 37.5 RMV @ 132 fsw| 5| 5| 5| 5| 5| 5| | B 75 RMV @ 132 fsw| 5| 5| 5| 4| 5| 4| | C 62.5 RMV @ 165 fsw| 5| 5| 5| 4| 5| 4| | D 62.5 RMV @ 198 fsw| 5| 5| 5| 4| 5| 4| | Rating System: 5=Excellent 4=Very Good 3=Good 2=Fair 1=Poor|

Continued

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| | Ease of Breathing | 4| 4| 4| 4| 4| | Different Positions | 3| 3| 3| 3| 4| | Dives Dry | 4| 4| 4| 4| 4| | Bubble Interference | 3| 3| 3| 3| 4| | Clearing Blow/Purge | 4| 3| 4| 4| 4| | Comfort | 4| 3| 4| 4| 4| | Adjustments | N/A| 3| 3| 3| 4| | ANSTI Breathing Simulator Results| | A 37.5 RMV @ 132 fsw| 5| 5| 5| 5| 5| | B 75 RMV @ 132 fsw| 5| 3| 5| 5| 5| | C 62.5 RMV @ 165 fsw| 5| 3| 5| 5| 5| | D 62.5 RMV @ 198 fsw| 5| 3| 5| 5| 5| | Rating System: 5=Excellent 4=Very Good 3=Good 2=Fair 1=Poor|