InDEPTH’s Holiday Rebreather Guide 2024

Original (2020) by Michael Menduno, Amanda White and Kenzie Potter. Subsequent yearly updates by M. Menduno. Lead photo and holiday images by Jason Brown, BARDO CREATIVE unless noted.  M2 xmas pics by Frauke Tillmans.

A Guide to Backmount, Sidemount and Frontmount Rebreathers

Go to Backmount Rebreathers | Go to Sidemount Rebreathers | Go to Frontmount Rebreathers

Sport diving rebreathers have come a long way since storied explorer Bill Stone trialed his 95 kg/209 lbs. fully-redundant “Failsafe Rebreather For Exploration Diving” (F.R.E.D.), and spent a cool 24-hours underwater as part of his paradigm-shifting 1987 Wakulla Springs Project. In retrospect, looking back over the last 30-some years, the “Technical Diving Revolution,” which emerged in the late 1980s to late 1990s, was ultimately about the development and adoption of rebreather technology. 

However, it took the fledgling tech community at least a decade to adapt mixed gas technology for open circuit scuba, including establishing the necessary supporting infrastructure, which was the first and necessary step in the move to rebreathers. A little more than a decade after Stone showcased FRED, British diving entrepreneur Martin Parker, managing director of then AP Valves, launched the “Buddy Inspiration,” the first production closed circuit rebreather designed specifically for sport divers, earning him the moniker, the “Henry Ford of Rebreathers.” [The brand name later became AP Diving] KISS Rebreathers followed a little more than a year later with its mechanical, closed circuit unit, now dubbed the KISS Classic. The rest as they say, is history, our history. 

Today, though open circuit mixed gas diving is still an important platform, rebreathers have become the tool of choice for deep, and long exploration dives. For good reason, with a greatly extended gas supply, near optimal decompression, thermal and weight advantages, bubble-free silence, and let’s not forget the cool factor, rebreathers enable tech divers to greatly extend their underwater envelope beyond the reach of open circuit technology. 

As a result, divers now have an abundance of rebreather brands to choose from. Accordingly, we thought it fitting this holiday season to offer up this geeky guide for rebreather shoppers. Want to find out whose breathers are naughty or nice? Here is your chance.

Your Geeky Holiday Guide

The idea for the holiday guide was originally proposed to us in 2020 by Divesoft’s US. General Manager at the time, Matěj Fischer. Interestingly, it didn’t appear to have been done before or subsequently. Our goal was to include all major brands of electronic and mechanical closed circuit rebreathers in back mount [which includes back mounted, and over-the-shoulder and front mounted with T-junctions,  counterlung configurations), as well as sidemount configuration in order to enable shoppers to make a detailed comparison. 

Veteran rebreather instructor Peter DenHaan, proposed that instead of using the term Back Mounted Counter Lungs (BMCL) we characterize these systems as either Back Routed Counter Lungs (BRCL) or Over-the-Shoulder Counter Lung (OSTCL) with a T-piece, noting that the two have very different work of breathing (WOB) characteristics. . 

The original guide also included Halcyon Dive Systems’ semi-closed rebreather, the RB80, and their more recent RBK sidemount unit, which have both been used successfully as exploration tools. We subsequently added the Mares Horizon. We soon added a section for front mounted rebreathers, which have grown in popularity and number over the last few years, and have continued to add units to this category. We also added Lombardi Undersea Research Ltd’s back mounted oxygen rebreather with back routed counter lungs (BRCL) designed for use by tech & scientific divers.

Please note, that while we strive to make the InDEPTH guide comprehensive there are a few older units like Innerspace Systems Corp.’s Megalodon and other models that are currently not included. There may be other brands that we have inadvertently missed. Our apologies. Contact us. We can update.

It’s The Concept, Stupid

The plan was to focus on the feature sets of the various rebreathers to provide an objective means to compare various units. But features by themselves do not a rebreather make. As Pieter Decoene, Operations Manager at rEvo Rebreathers, pointed out to me early on, every rebreather is based on “a concept,” that is more than just the sum of its features. That is to say that the inventors focused on specific problems or issues they deemed important in their designs; think rEvo’s dual scrubbers, Divesoft’s redundant electronics, or integration of open and closed circuit in the case of Dive Rite’s recently launched O2ptima Chest Mount. Shoppers, please consider that as you peruse the various offerings. My thanks to Pieter, who helped us identify and define key features and metrics that should be considered.

Though not every unit on the market has been third-party tested according to Conformitè Europëenne (CE) used for goods sold in the European Union, we decided to use CE test results for some of the common feature benchmarks such as the Work of Breathing (WOB), and scrubber duration. For vendors that do not have CE testing, we suggested that they use the figures that they publicize in their marketing materials and asked that they specify the source of the data if possible. As such, the guide serves as an imperfect comparison, but a comparison nonetheless.

Also, don’t be misled by single figures, like work of breathing or scrubber duration as they serve only as a kind of benchmark—there is typically a lot more behind them. For example, whether a rebreather is easy to breathe or not is a function of elastance, work of breathing (WOB) and hydrostatic imbalance. In order to pass CE, the unit must meet CE test requirements for all three issues in all positions from head down, to horizontal trim, to being in vertical position (Watch that trim!), to lying on your back looking upwards. It’s more difficult to pass the tests in some positions versus others, and some units do better in some positions than others. 

The result is that some of the feature data, like WOB, is more nuanced than it appears at first glance. “The problem you have is people take one value (work of breathing for instance) and then buy the product based on that, but it just isn’t that simple an issue,” Martin Parker explained to me. “It’s like people buying a BCD based on the buoyancy; bigger is better, right? Wrong! It’s the ability of the BCD to hold air near your centre of gravity determines how the BC performs. With rebreathers you can have good work of breathing on a breathing machine only to find it completely ruined by it’s hydrostatic imbalance or elastance.”

Due to their design, sidemount rebreathers are generally not able to pass CE requirements in all positions. Consequently, almost all currently do not have CE certification; the T-Reb was the first to have a CE certification with exceptions. However, that does not necessarily mean that the units haven’t been third-party tested. 

Note that the guide, which is organized by type of rebreather, then alphabetically by manufacturer, contains the details for each of their featured models. In addition, we are in the process of updating a master downloadable spreadsheet for each type of configuration; back, side and front mounted rebreathers. We will post these in the InDEPTH newsletter when they are completed and link them under DIVE DEEPER at the end of the guide.

We are in the process of updating a master downloadable spreadsheet for each type of configuration; back, side and front mounted rebreathers. We will post notifications and links in the InDEPTH newsletter when they are completed and link them under DIVE DEEPER at the end of the guide.

Lastly, I’d also like to give a shout out to British photog phenom Jason Brown and the BARDOCreative Team (Thank you Georgina!), for helping us inject a bit of the Xmas cheer into this geeky tech tome [For insiders: this was Rufus and Rey’s modeling debut!]. Ho, ho, hose!

With this background and requisite caveats, we are pleased to offer you our Holiday Rebreather Shoppers’ Guide 2024 Edition. Happy Holidays!!

Note – Most prices shown below were specified by manufacturer before tax.

Backmount Rebreathers

Note – Vobster Marine Systems were acquired by UK-based NAMMU Tech, which used the technology from the VMS Redbare (formerly the Sentinel) to create: Atlas CCR.

Sidemount Rebreathers

Frontmount Rebreathers

DIVE DEEPER:

GUE.TV: You can find all of the Rebreather Forum 4 presentations here on REBREATHER FORUM 4

Michael Menduno is InDepth’s editor-in-chief and an award-winning reporter and technologist who has written about diving and diving technology for 30 years. He coined the term “technical diving.” His magazine aquaCORPS: The Journal for Technical Diving (1990-1996), helped usher tech diving into mainstream sports diving. He also produced the first Tek, EUROTek, and ASIATek conferences, and organized Rebreather Forums 1.0 and 2.0. Michael received the OZTEKMedia Excellence Award in 2011, the EUROTek Lifetime Achievement Award in 2012, and the TEKDive USA Media Award in 2018. In addition to his responsibilities at InDepth, Menduno is a contributing editor for DAN Europe’s Alert Diver magazine and X-Ray Magazine, a staff writer for DeeperBlue.com, and is on the board of the Historical Diving Society (USA)

Amanda White is the managing editor for InDepth. Her main passion in life is protecting the environment. Whether that means working to minimize her own footprint or working on a broader scale to protect wildlife, the oceans, and other bodies of water. She received her GUE Recreational Level 1 certificate in November 2016 and is ecstatic to begin her scuba diving journey. Amanda was a volunteer for Project Baseline for over a year as the communications lead during Baseline Explorer missions. Now she manages communication between Project Baseline and the public and works as the content and marketing manager for GUE. Amanda holds a Bachelor’s degree in Journalism, with an emphasis in Strategic Communications from the University of Nevada, Reno.

Kenzie Potter Stephens is a production artist for InDepth as well as part of the GUE marketing team. She earned her BS degree in Industrial Engineering and Marketing at the Karlsruhe Institute of Technology (KIT) in Germany, which assists her in using her multicultural upbringing to foster international growth within the community. In addition to her activities as a yoga teacher and an underwater rugby trainer, she has completed her GUE Tech 1 and Cave 1 training and is on her way to becoming a GUE instructor. Not letting any grass grow under her feet, she has also taken on a second major in biochemistry in order to create a deeper understanding of our planet’s unique ecosystems as well as the effect of diving on human physiology.