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How We Test Scuba Diving Regulators
The in-water test was conducted at Alexander Springs in central Florida by a team of divers. Equipped with underwater slates, divers evaluated each reg in the categories below, assigning a score from 5 (excellent) to 1 (poor), and recorded their observations and comments about the comfort and performance of the regs while they were actually being used.
|Ease of Setup||How first-stage hose/port arrangement helps or hinders attachment and use of BC, octo, SPG, etc.|
|Ease of Breathing in Swimming Position||How well does the regulator deliver air when you are propelling yourself forward in a standard swimming position?|
|Ease of Breathing in Face-up Position||How well does the regulator deliver air when you are at depth and looking up toward the surface?|
|Ease of Breathing in Head-down Position:||How well does the regulator deliver air when you are at depth and in an inverted, head-down position?|
|Wetness in Normal Swimming Position||During normal swimming, how dry does the regulator breathe?|
|Wetness in Head-down Position||When in odd positions, including head-down and face-up, how dry does the regulator breathe?|
|Bubble Interference||Taking into account that all regulators have bubble interference to a certain degree, how well does the reg deflect bubbles from your view?|
|Ease of Clearing||How difficult is it to clear the regulator by exhaling into the mouthpiece or using the purge?|
|Purge Stiffness||How difficult is it to clear the regulator by exhaling into the mouthpiece or using the purge?|
|Venturi Level Adjustment||Is the Venturi lever easy to find and use? Is it effective at blocking free-flows on the surface and at depth?|
|Breathing Adjustment Knob||Is the adjustment knob easy to find and use? Does it do its job in a reasonable manner?|
|Comfort of Second Stage||Are the shape and weight such that they help prevent jaw fatigue?|
The objective testing utilized an ANSTI wet breathing simulator to measure the effort — work of breathing — required to move air through a reg as it is subjected to a precise series of depths and breathing rates. The testing was done at Dive Lab, a commercial testing facility in Panama City Beach, Florida.
Throughout the test, the simulator monitors effort required to “breathe” in and out, measuring the work of breathing. As depth and breathing rate increase (and with it, the density of the air being moved), the work gets harder.
If a reg performs well while meeting our standard test scenarios — the toughest of which an extremely fit scuba diver would find difficult to keep up for more than a few minutes — we push it into even more extreme conditions
We don’t test on the simulator for a pass/ fail grade, but rather to objectively gauge performance in carefully controlled conditions. You can see how each reg performed on the breathing simulator in the charts that accompany the reviews.
ANSTI breathing simulator results shown here are based on a score of 1 to 5, where 1 represents poor and 5 represents excellent performance with work-of-breathing measures of 1 joule per liter or less at carefully regulated depths and breathing rates and volumes.
Find the in-depth information on the ANSTI scuba regulator test.
Scubapro has put together its MK21 first stage and C350 second stage for what it bills as the most compact reg in its line. It also turns out to be one of the best pairings since chocolate and peanut butter. Test divers rated the MK21/C350 very good across the board, praising it for ease of breathing, dryness (even in head-down position), and comfort of the lightweight second stage (though some of our testers found it a tad noisier than they liked). Uncommon at this price point, the breathing adjustment is precise and effective, to the degree that some divers felt they were tempting free-flow by opening it to the max. But the Venturi switch (a sensibly sized, easy-grasp lever rather than the tiny tabs we’ve complained of on some Scubapro regs) proved bulletproof. On the breathing simulator, the reg really flexed its muscles. After it took excellent scores at all our standard test depths and breathing rates, we pressed it further; it didn’t breach our test parameters until it hit 294 feet. Comfortable and capable, the MK21/C350 is our Testers Choice in this category.
Price: $479 Contact: scubapro.com
Cressi Compact Pro/MC9 SC
Cressi has continued to refine the design of its aptly named Compact, which uses a plastic that conducts heat like metal, boosting cold-water performance while reducing weight. Divers rated the latest version, which has an environmentally sealed first stage, one of the driest regs here in both upright and head-down positions. Its Venturi control — well-marked and mounted on top where it’s easy to see and access — was rated among the best in its category at stopping free-flows. Some divers found the purge a bit stiff, and thought the Compact had a little extra bubble interference when head-up — not really a surprise, given its somewhat abbreviated exhaust ports. But above all, what divers liked about the Compact Pro was the extremely lightweight second stage (barely 5 ounces on our scale) that made the reg essentially weightless underwater, translating into zero jaw fatigue and tying the top score for second-stage comfort.
Price: $419.95 Contact: cressiusa.com
Hollis 100LX/ DC3
With its lustrous chrome finish, braided hose and sleek design details, the 100LX looks like a more expensive reg than it is. It dives the same way, earning top scores in its category for ease of breathing in swim position. Divers praised the reg’s soft, predictable purge and scored the second stage very good for comfort. One of the few signs of cost-consciousness was the single HP port (there are four LP ports), but divers still rated the arrangement very good for setup. Like most regs in the category, there’s no breathing adjustment, but the 100LX didn’t seem to need one; it flowed air with just a hint of inhalation, although some divers found it a little too eager, as though on the edge of free-flow. But with the Venturi switch — easy to grasp and smooth to operate — in predive it was hard to make it free-flow at the surface, even intentionally. With impressive performance and attention to detail at an attractive price, the 100LX is our Best Buy.
Price: 399.95 Contact: hollis.com
Sherwood Scuba Oasis
The redesigned purge cover with distinctive green highlights gives the latest version of the Oasis a very different look, but fortunately it retains the characteristics we liked in the earlier modeI. It has the same elliptical shape, and inside there are still moisture-retention vanes that help prevent dry mouth by capturing the moisture in exhaled breath and returning it on inhalation. Most important, the new model proved to still be an easy-breather, with divers scoring it very good for ease of breathing in all positions. And while the second stage looks a little wide, it’s actually quite light in the mouth, helping the Oasis earn a very good score for comfort. One unwelcome trait that carried over is a little more wetness in head-down position than most divers wanted, though it was no worse than most regs here. Above all, the updated Oasis still delivers relief for a parched throat — and does so more smoothly than ever.
Price: $460 Contact: sherwoodscuba.com
The very light, compact second stage of the RS1001 helped the reg collect very good scores for comfort from test divers, who also found the reg to be notably easy breathing, especially in normal swimming position and even when head-down (though a little less so when face-up). The Venturi switch was very effective at killing free-flows on the surface, but its score suffered just a bit because some divers, especially those with larger hands, found it tricky to get a good grip on the lever, which is quite small and close to the body. Some divers also found the reg slightly wetter than they preferred, though this was more pronounced when head-down — a point where scores slipped for almost all of the regs here. On the ANSTI simulator, the RS1001 showed why divers rated it an easy breather. It racked up excellent scores across the board by posting some of the lowest work-of-breathing numbers of any reg in our test.
Price: $429 Contact: tusa.com
XS Scuba Brawn
One of the first new regs we’ve seen from XS Scuba in a while, the new Brawn comes in at the lower price end, and as with many of its cost-saving competitors, it’s built around a simple unbalanced-piston first stage. But unlike most, it’s been paired with a pneumatically balanced second stage that helped it turn in a good showing both in the water and on the simulator, where its performance was rated excellent at recreational depth at a moderate breathing rate, and good throughout our test range. Test divers rated the Brawn very good for comfort and for ease of breathing in all positions. The Venturi lever was effective and easy to operate, and the purge was soft and progressive. One gripe was the limited mounting options posed by the arrangement of the single HP and four LP ports on the first stage barrel, which seemed for some divers to leave one hose inconveniently located. But for an extremely attractive price, the Brawn delivered very credible performance and comfort.
Price: $330 Contact: xsscuba.com
XS Scuba Inspire
The second of the new regulators we tried from XS Scuba this year, the Inspire impressed us as soon as we pulled it from its box — and even more so once test divers got it in the water. It has details not that common at this price range — a breathing-resistance adjustment, braided hose, rotating first-stage turret — but even more, a look and feel of quality. From the deep chrome on the first stage to the lightweight metal of the diaphragm ring and breathing knob, it’s a nice piece of work. When we got it into the water, we found it’s not all looks either. Divers rated it very good in every test category but two; it was scored just good for dry breathing when head-down but excellent for its soft, predictable purge, the highest score in the category. On the simulator, the Inspire took scores of excellent and very good, and breathed within our demanding test parameters down to 296 feet. All in all, we’d call that an inspiring performance.
Price: $470 Contact: xsscuba.com
It’s a bit misleading to put Beuchat’s new V-Twin into this price category, since unlike the other regs here, it comes with an octo. Which brings us to its unique feature: The first-stage has dual mechanisms that operate independently, one for the primary second stage and the other for the octo and accessories like a BC inflator. Of course, that redundancy won’t make much difference in emergencies such as out of air, ruptured hose or ice-induced free-flow. However, Beuchat says the novel configuration will provide two divers with optimum performance in an emergency, even down to 50 meters (164 feet). Our testing didn’t include that sort of scenario, but on the simulator, the V-Twin was rated excellent at recreational depth and very good beyond. Test divers gave it high marks for dry, smooth breathing — including one of the top scores for ease of breathing in swim position. Call the V-Twin a novelty, but it’s a dry, silky-breathing one.
Price: $527 Contact: beuchat-diving.com
Hollis 200LX/ DCX
This is the sort of reg you’ll find gear-heads fondling — stroking the glossy highlights and matte-black body, and running the breathing adjustment in and out to hear the click of the little clutch inside. (In case our own reg asks, we never called the 200LX pretty.) But you don’t need to be a gear geek to like the way the reg breathes. Divers gave it an excellent score for ease of breathing in swim position, and it validated those findings on the breathing simulator, where it matched the top scores in the category. Divers also gave the second stage a very good score for overall comfort, helped by the easy-to-operate Venturi and breathing adjustments that didn’t require levering the mouthpiece around in your mouth. Some divers found the reg a little wetter than they liked when face-up and thought the purge was a bit aggressive. But overall the 200LX delivered smooth, easy performance as well as touches like the braided hose, rotating turret, and a quality feel and finish.
Price: $624.95 Contact: hollis.com
Scubapro MK25 EVO/ A700 Carbon Black Tech
You might need to take a deep breath before you tackle its full name, let alone its price. But get this reg in the water, and any breath you take will be as smooth as warm butter. It moves between exhalation and inhalation so seamlessly that you’re scarcely aware of it. “It just starts flowing air when you want it,” wrote one diver. The breathing adjustment, rated best in the test, allowed precisely dialed-in resistance. On the simulator, the reg took excellent scores at rec depth and very good beyond. Pushed beyond our regular test depths, it kept going and going, finally hitting our test parameter limits at 336 feet. Yes, it’s flashy, but that glossy finish on the lightweight metal body protects from dings and damage, while the handmade carbon-fiber diaphragm cover shaves grams where they’re most critical. This is a reg that looks the part, and can play it too. It is our Testers Choice in this category.
Price: $1,240 Contact: scubapro.com
Sherwood Scuba Maximus
The Maximus has returned to the Sherwood line after a major redesign. It has some of the same familiar design elements — the elliptical second stage and 90-degree swivel for an underarm hose placement — but with lots of changes in the details, both inside and out. The most obvious are the diaphragm cover, which has cutouts in the corners with an underlying mesh, giving it a cool muscle-car-grill look, and the breathing adjustment, which is now on the left side, rather than at the hose inlet as it formerly was. On the simulator, the Maximus proved a capable breather, taking scores from excellent to very good. Test divers rated it very good for ease of breathing in swim and head-down positions, and for dry breathing in all positions. It was also rated very good for comfort, with several divers noting that, while the second stage seems large at the surface, it has a very light feel in the water, and the 90-degree swivel kept it from pulling or levering on their mouths.
Price: $690 Contact: sherwoodscuba.com