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Reviewed by our Gear Geeks:

The Best Rebreathers in 2021

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Our experts at work

We gave our Gear lovers one job:
Research multiple Rebreathers and write reviews of the best.

The result is 5 of the best Rebreathers on the market today.

torben lonne

The DIVEIN Staff

Editors & Writers at DIVEIN.com
We are instructors & divemasters

If you’re interested in a rebreather (including closed and semi-closed systems), you’ve certainly been a scuba diver for some time. The increased depth and bottom time can really take your diving experiences to a whole new level. It opens up different kinds of dive sites that are beyond open-circuit scuba.

A rebreather is often employed by technical divers, including photographers and marine archaeologists, etc., and sometimes at shallower depths.

All the added benefits of rebreather diving come at a cost — for the unit itself, for consumables such as sorb (soda lime), and for any extra training you need. So it’s safe to say that buying an expensive rebreather isn’t something a diver should take lightly. You want to get a unit that’s right for you and your intended diving the first time around.

Let’s take a closer look at five of the top rebreathers on the market in 2021. Read our guide below for tips and things to consider.

Best Rebreathers in 2021

The ever-popular JJ CCR can be seen wherever rebreather divers are. In many ways, it’s somewhat like the 4X4 of the rebreather world. The unit is machined out of solid anodized alloy, and comes with an axial scrubber as standard. When your diving progresses in line with your skill level, there is an option to upgrade the scrubber to a radial model.

You can equip the JJ with up to 4 tanks of 2 to 12 liters of different gas mixtures and it comes with APEKS first stages. A CE rating means this unit is certified for safety by a third-party agency.

Specs & Features:
  • Robust aluminum housing
  • Secure up to four tanks
  • User repackable soda lime canister
  • Stand is heavy-duty
  • Integrated handle
  • Back-mounted counter lungs
  • Redundant power supply: One battery for the controller, one battery for the HUD and two parallel batteries for the solenoid.
What we like:
  • Plenty of options for after-market add ons and additions
  • Common unit so easier to find service persons and centers
  • Stands well by itself
  • Three lights on the HUD indicate each cell
  • A good unit for beginner CCR divers
What we don’t like:
  • The JJ is BIG, not ideal for travel but that said, plenty of divers still find ways around this
  • Only a back-mounted counter lung option, not customizable like some units

You can find more info on the JJ CCR’s specs and features here. Note that there are differences between the CE model and the International model in the manual diluent valve.

The Hollis Prism 2 is a pretty sleek-looking unit, and it has got some serious technical chops to boot. Plus there are a few options for divers, such as choosing between electronic or manual control options and back-mount or front-mount counter lungs. Explore open seas, caves, or wrecks with ease.

Tested by ANSTI at 100 meters, the Prism 2 had the lowest work of breathing of any mixed gas CCR unit. Tanks and valves will need to be purchased separately.

Specs & Features:
  • Unit weight of 47 pounds in standard configuration
  • Split counter lungs
  • Both front and back-mount counter lung configurations
  • Counter lung drains to easily remove water during a dive
  • All gas lines external to the breathing loop
  • Automatic diluent valve
  • Manual diluent valve
What we like:
  • Highly customizable, plenty of different options for add-ons, configurations, and dive styles
  • Rear-mounted radial scrubber
  • Excellent work of breathing
  • CE approved
  • Hollis has an excellent reputation for after-sales support
What we don’t like:
  • One of the finickiest scrubbers to pack in the industry
  • BOV is sensitive to freeflow on the surface

Learn more about the Hollis Prism 2 here.

The Divesoft Liberty first hit the market in 2014, since then, the popular CCR unit has undergone some significant changes. As demand for customizable options has grown, so too has the Liberty’s possible configurations. Divesofts CCR Liberty can be ordered in the following configurations: FMCL, BMCL, Sidemount, Light and Heavy.

Liberty has been designed to be a “complete fault-tolerant” unit, meaning that even if one electronic part has an issue, it won’t cause the whole unit to break down. A long battery life, air integration, defective solenoid detection, and in-built GPS are among the other new features.

Specs & Features:
  • Radial scrubber
  • Options for back, front and side-mount counter lung configurations
  • Liberty light version for travel
  • Bailout valve
  • Two independent computers
  • ADV-BOV or Diaphragm Automatic Diluent Valve
  • Manual addition valve
What we like:
  • 2021 version of the Liberty CCR is set to be a game-changer
  • Sidemount unit and Liberty Light are ideal for travel
  • Very good work of breathing
  • CE certified
  • Redundant electronics
What we don’t like:
  • We may have to sell a kidney to purchase the 2021 version. You only need one, right?!
  • The sheer number of bells and whistles may be too much for new and/or inexperienced CCR divers

To delve deeper into the Liberty CCR and all the available options, click here.

The Triton CCR is something a little different. It is a chest-mounted mechanical CCR produced by M3S in France. Its manufacturers have given this unusual unit a trial by fire in French cave systems and it’s the first MCCR to receive CE ratings for a depth of 100 meters with Trimix.

We think the Triton would be excellent in high-current environments and when jumping off skiffs. It should also have decent work of breathing because it’s on the chest and the hydrostatic pressure is much lower. Another application would be using this tiny unit as a bail-out device on deeper, very technical dives. At a weight of just 7 kg (without tanks or lime), it’s flight path ready too.

Specs & Features:
  • Color-coded click-lock system
  • PPO2 display controlling a HUD
  • Petrel 2 or NERD 2 computer options
  • Supports one 1.5-liter O2 tank
  • Used in conjunction with other dive systems
  • 12.2 kg ready to dive weight
  • Kevlar bag holds lime and the counter lungs
What we like:
  • Innovative product, truly one of a kind
  • Excellent for travel, no excess baggage fees here
  • Good work of breathing
  • CE certified
  • A color-coded system means it’s near impossible to make a mistake setting this up
What we don’t like:
  • Its diminutive stature naturally means the Triton lacks the functionalities and range of other CCR units

Learn more about the Triton CCR here.

The X-CCR by iQsub offers some serious expedition credentials. The unit features CO2 monitoring and high-pressure sensors that display both diluent and O2 info on the primary handset, something many CCR divers will appreciate.

Choose from expedition or travel-sized canisters and over-shoulder or back-mount counter lungs, there are also seven different options for secondary PPO2 monitoring, including the Petrel 2 EXT. These are just two of the options you have with the standard unit. And with heaps of add-ons available, customizing your X-CCR to preference is a breeze.

Specs & Features:
  • Radial scrubber
  • Shrimp bailout valve (BOV)
  • Removable O2 cell cartridge
  • QuickLoc attachments on all hoses and BOV
  • Manual Addition Valves (MAVs) for O2 and diluent
  • Automatic Diluent Valve (ADV)
  • Three-liter steel O2 and dil tanks
What we like:
  • Secondary handset (Petrel 2 or Wiekamp OTSC) acts as a redundant PO2 display and provides decompression info
  • Plenty of customization options, both with the standard unit’s options and as after-sale add-ons
  • Travel and expedition-size canisters
  • Built to last and incredibly robust
  • A pretty bad-ass-looking unit!
What we don’t like:
  • Limited support and service options for divers outside Europe and the US. iQsub is a Czech company and SubGravity, the US distributor, provides assistance when needed in the state. But we wonder how much support is available to X-CCR divers in New Zealand, for example.

Read more about the X CCR by iQsub here.

Things to consider before buying a rebreather

With that in mind, before diving into the top rebreathers on the market in 2021, let’s take a closer look at the things you should consider before buying a rebreather.

Whether you’re currently researching your first rebreather or you’re changing to a new unit, there are a few things you’ll need to think about. Not all of these considerations apply to all divers, but we’ve tried to cover some essential bases.

Are you experienced enough for rebreather diving?

In 2013, Dr. Andrew Fock, a hyperbaric specialist at the Albert Hospital in Melbourne, Australia, released a paper on deaths in the rebreather diver community. After analyzing data from 1998 to 2010, Dr. Fock concluded that rebreather diving was ten times more dangerous than open-circuit scuba. He also noted that most incidents were a result of “pilot error.”

We quote this statistic not to scare you off rebreathers, but to remind rebreather divers-to-be that you should have the training and dive experience needed to dive with these units. Ideally, you have a working understanding of the science of diving and excellent diving skills. As Jill Heinerth puts it: “This is not a time to be struggling with academic knowledge or diving skills.”

Do you understand the basics of rebreather diving?

Before you can even begin comparing rebreather units, you need to understand the fundamentals of rebreather diving. Learn more about standard rebreather components including what they do and how each part works.

Familiarize yourself with the different options and the differences. For example, you should know how radial and axial scrubbers vary, the key differences between back-mount and chest-mount counter lungs, the relative pros and cons of bailout valves or BOVs (also called OCBs) and DSVs, and other key matters.

If all the acronyms have your head spinning or you lack a rudimentary understanding of these terms, you’ll need to investigate further or get some training.

We recommend The Basics of Rebreather Diving by Jill Heinerth, cave explorer extraordinaire, to get you started.

In addition, Rebreathers Simplified, a 140-plus page guide to choosing a unit, will be helpful to new rebreather divers. Another commonly recommended book is Mastering Rebreathers by Jeff Bozanic, but be aware that this is now more than 20 years old.

We get it. You’d rather go diving than study, right? But if you’re paying more than US$10,000 for a rebreather, it only makes sense to know what you’re buying and how it operates.

Who will train me?

Before you purchase a unit, it makes sense to think about who will train you to use it! Find an instructor who has experience with the unit you’re considering. Ideally, they’ll know all the ins and outs of a model and can pass this insider information on to you.

Understand that you may need to travel to your instructor, so factor in travel costs in addition to training fees. It’s not smart to settle for second best when it comes to your rebreather education, choose a respected instructor with plenty of experience. You may find that their schedules are busy, so be prepared to book well in advance.

What is the rebreather CE 14143?

In Europe, all rebreathers must meet a strict set of standards. The CE 14143 compliance rating shows that a unit has obtained the standards required for safe operation. Factors examined during the certification process include a unit’s work of breather, sensor tracking functions, and other key elements.

In the US, however, these requirements are not mandatory. Nevertheless, many manufacturers choose to make CE-compliant rebreathers. When you choose a unit, it’s always smart to go with one that has been examined by a third-party regulating agency. Even if you live in the US, look for CE compliance in a rebreather.

Consider your budget, but don’t try to save too much!

As with most major purchases, your budget will, to an extent, dictate the unit you can purchase. But as the saying goes: “in for a penny, in for a pound.” It’s kind of similar with rebreathers because if you’re already spending around US$10,000 on a unit, an additional $200 can’t break an already broken bank!

Trying to save, and giving up functionality or features you want, could mean ending up with a unit that’s not right for you. And if that happens, you’ll probably sell the unit and buy what you should have bought in the first place!

Will you travel with your rebreather?

Rebreathers aren’t small pieces of kit, and some are more suited to travel than others. If you plan on taking your rebreather overseas, find out how easy it is to travel with a certain unit. Assess whether it can be broken down into parts that will fit inside bags or cases that match the airline’s size and weight requirements.

In addition, consider all the spare parts and accessories you’ll need to take with you. The list might be longer than you think. The Dirty Dozen Expeditions has an excellent packing-list resource for divers traveling with a CCR, you can find that list here.

Servicing matters

Rebreathers take a lot of ongoing care and maintenance. Ignoring minor (or what you think are minor) issues is not an option, and it could even lead to a major in-water issue. So be prepared to service your rebreather after 12 months of use or 15 months after the date of production.

With that in mind, it makes sense to choose a unit that you can have serviced in your home country, or close by, at least. There’s little point in buying a unit that can only be fixed in Europe, for example, if you’re based in the US. Before buying, find out where a given unit can be serviced.

SCR or CCR?

Semi-closed (SCR) and closed-circuit rebreathers (CCR) each have distinct advantages and disadvantages. Most SCRs are simpler, mechanical units that don’t rely heavily on O2 sensors or electronics. Many rebreather divers would argue that this means the chances of a failure are lower, and, should a failure occur, that it’s easier or more intuitive to remedy.

CCR units, on the other hand, generally rely on electronics and O2 sensors to adjust the diver’s breathing mixture. This means the diver receives a tailored breathing gas that’s perfectly suited to the diver’s depth and time. Because of this, CCR units are considered more flexible. The downside is that they’re more complex and certain failures aren’t easy to immediately diagnose and remedy.

CCR units can be either electronic (ECCR) or manual (MCCR). With the former, a computer constantly measures the oxygen percentage in the breathing loop and maintains an oxygen partial pressure (PPO2) set point. In contrast, MCCR units require input from the diver. He or she will need to monitor the oxygen percentage in the breathing loop and inject more as needed to maintain a set PPO2. This entails a higher level of diver diligence and awareness.

Some types of diving are better suited to CCR and others to SCR. Determine what kind of dives you’d like to do with your rebreather, talk to experts in that field and find out what their unit of choice is.

That all said, there’s an argument to be made that SCR units are becoming less popular, despite the efforts of some training agencies. We spoke to several top-level CCR divers, and each told us the same thing: most SCR divers become CCR divers within a few years. If you think the same thing might happen to you, consider skipping the SCR part and going directly to CCR.

What do you guys think of our choices? Drop us a comment below and give us your thoughts!

1 Comment

  1. Dr JoJo

    Poor choice. I’ve been diving an Inspiration for more than 20 years. There is one thing you have forgotten about, and that is the percentage of successful dives, or the numbver of dives lost to problems once on the boat and away from land.

    I’ve lost count of the number of dives that have been called off for technical problems with buddies RBs. The Inspiration just gets the job done in a very uneventful way. Triton? never see them, JJ? great when they work. Hollis? always having niggly problems. Liberty? you’re right, way over priced for what it is, you will have to sell a kidney.

    You might not like the APD machines, but from my experience, there are far more of them out there than the others, and they’re about the most reliable that there are available, they’re there, getting the job done.

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