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Reinventing the rebreather

SE7EN+ redefines what we have come to know as a rebreather. Building upon traditional rebreather design but embracing technological innovation has lead to the SE7EN+ with capabilities beyond anything seen before. The patented oxygen sensor management and the groundbreaking oxygen sensor technology ensures that rebreather safety is no longer a guessing game. It is easy enough for a beginner to master, advanced enough to appease the professionals.



Automated safety tests, in-dive gas adjustments and situational predictions are just the tip of the iceberg that opens up rebreather diving for everyone.

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Get automatic, choose manual.

A rebreather built for all divers. While giant strides in automating the SE7EN+ have opened the world of recreational rebreather diving, equal attention has been given to designing a rebreather with full controllability. Manual gas injection, trimix blends, 100+ m deco diving to name a few, the SE7EN+ has it all.

Whenever. Wherever.

Resilience has always been one of Poseidon's cornerstones, the SE7EN+ is no exception.

Carefully chosen light-weight and tough materials encase the precious components from the harshest of environments while reducing the weight and size for a more comfortable fit, and easier travel. A perfect balance between robustness and mobility.

Tested and certified for the icy blue waters of the north, to the vibrant reefs of the tropics, there are few places on this planet where the SE7EN+ doesn't excel.

The most capable rebreather with some serious brain power.

Within the core of the SE7EN+ lies one of the most advanced rebreather controllers ever made with the best oxygen sensor ever invented. With Poseidon's G7 electronics, it senses every move, predicts the future and offers information long before any critical situation arises. The patented oxygen sensor management sets a new standard in the industry.

The rebreather that grows with you.

Aside from allowing easier maintenance and understanding of the system, modularity also brings with the major advantage of easily modifying and configuring your rebreather. Upgrade your rebreather as your diving skills progress. You will never be limited by a SE7EN+

Rigorous pre-dive tests.

Pre-dive safety-tests and sensor calibrations automatically ensure that all systems are running correctly before every dive. Get in the water without any doubt that the SE7EN+ on your back is good to go.

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A next generation mouthpiece.

Lightweight, comfortable mouthpiece with Poseidon’s patented integrated Bail-out-valve (BOV). Change from CC to OC with a simple twist, activating a bail-out regulator with Poseidon Xstream performance.

Se7en+ editions

all good things come in three

The Sport, Rec and Tec editions are perfect platforms on which to start and continuously build upon. The modularity of the SE7EN+ knows no limits, which is why any of the packages can be upgraded and modified as you progress, or you can configure to your unique setup from the start. All packages comes with a choice of oxygen sensors and cylinders. See the Tech Specs for more details.

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A fully capable SE7EN+ configuration at an exceptionally affordable price. Simple enough for a beginner to master yet expandable to a technical unit capable of 100+ m.

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A premium package with our M28 computer and cover included, for the sports diver who plans to explore further.

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The Tec edition pulls no punches. Perfect for the technical diver who wants it all, full manual control when needed and still the convenience and unparalleled safety of a SE7EN+.

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better than the sum of its parts.

A true exploration of the deep begins when the lines between you, your rebreather, and the ocean are erased. The SE7EN+ achieves the same level of uniqueness as your diving ambitions through its expansive modularity and configurability.

Solid-state O2 Sensor, a new era in oxygen sensing.

Poseidon’s patented state of the art oxygen solid-state sensor is factory-calibrated and absolute, delivering unsurpassed operating life, shelf life and calibration stability.

It's time to leave the analog, galvanic era, and move on to the digital, optical age.

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Choose between the classic Rebreather Paddle Display or the cutting-edge Poseidon M28 dive computer with sleek graphics and endless functionality. The M28 is capable of running the rebreather decompression algorithms and thus serves as a redundant system when paired with the SE7EN+.

M28 Dive Computer


Rebreather Padel Display


Smart Batteries

Powers the SE7EN+ for up to 12 hours of diving. Each color unlocks a new level of diving, from 40 m dives with the Green Rec 40 all the way down to 100+ m, deco and hypoxic trimix diving with the Black Deep.

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Green Rec 40


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Yellow Deco 40


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White Deco Trimix 60


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Black Deep


Rebreather diving

Dive longer, safer, and closer to wildlife.

Going from scuba diving to rebreather diving is like stepping out of an old biplane and into a supersonic jet. Well, maybe with a bit less noise. Explore further, longer and deeper. Get so close to marine life that you almost become apart of it. This is the next step in diving, so don't miss out on it.

Get closer to marine life

Rebreathers don’t create bubbles or noise, making you a natural part of the underwater environment.

Underwater photography and videography

Marine life will come close for that great shot without distracting bubbles in the frame or bouyancy changes affecting your aim.

Dive in comfort

Rebreathers circulate warm, humid gas at ambient pressure, so it’s just like breathing above surface!

Explore the underwater

Rebreathers use gas efficiently, allowing you to stay underwater for several hours, so you can take your time and enjoy the little (and big) things!

How does a Rebreather work?

A rebreather system circulates breathing gas around the diver allowing them to “re-breathe” the air, instead of exhaling gas straight out into the water as in a scuba system. This makes rebreathers highly efficient as well as silent and bubble-free!

Key Advantages of rebreather diving

While a rebreather isn’t the best choice for every dive and every diver, it is the best choice for many divers and many dives. Rebreathers have the following key advantages over traditional scuba / open circuit:

A rebreather system is less noisy than an open circuit system, making the interaction with marine life more intense and up close, as wildlife will approach you rather than swim away from you.

The duration of a dive on a rebreather system is generally much longer which means that you can either stay down longer in one dive or do several repetitive dives without the need to re-fill your cylinders. The reason for this is that you will not use up your gas as fast as on a normal scuba system, because you are re-using gas the whole time, making the rebreather 96% efficient in comparison to 4% efficiency during an open-circuit dive. Your gas costs will be reduced, especially when you venture into technical diving. No decompression time is far greater on the rebreather system as it makes sure you have the optimal gas mix at every depth, therefore minimizing the intake of nitrogen. If you are a certified Nitrox diver, you can compare it to having a nitrox blender on your back that makes sure that you have the best mix at every depth.

An open circuit system gives you cold and dry gas, but on a rebreather you will get moist and warm gas, which is much more comfortable to breathe while diving. There is no need for deep breaths because the loop is an extension of your lungs. You only need to make sure that you continually breath normal breaths. Your buoyancy will not be altered by the way you breathe; it will only be changed when you add gas to your buoyancy device.

Why dive the Poseidon SE7EN+?

From the moment you first see a Poseidon SE7EN+, you’ll know that the world of diving has changed. Stylish, rugged good looks decorate and protect the most powerful dive computer ever built. Automated pre-dive and in-dive safety checks make rebreather diving easier and safer than ever before. Versatile technology makes the SE7EN+ suitable for first-time divers, advanced technical divers and anyone in-between. The Poseidon SE7EN+ is the only rebreather you’ll ever need!

How Poseidon SE7EN+ technology works.

All closed circuit rebreathers use oxygen, diluent (air/trimix), a breathing loop, counter-lungs, a mouthpiece to deliver the breathing gas, a scrubber to remove the carbon dioxide from the system and a method to replace the metabolized oxygen. That’s the easy part and where other rebreathers stop but Poseidon SE7EN+ technology really starts!

What makes the Poseidon SE7EN+ unique is the way in which it manages the gas in the breathing loop. The oxygen sensors detect the PPO2 in the breathing loop and solenoids automatically inject oxygen as required to maintain the appropriate PPO2 for the diver’s current depth. The SE7EN+ diver does not need to adjust PPO2 set points or manually maintain a set point; the SE7EN+ does it all for them.

The Poseidon SE7EN+ is an example of technology at its best; taking a complex process and making it beautifully simple. So simple, in fact, that the SE7EN+ diver can just enjoy the dive!

Throughout the dive, Poseidon safety technology is monitoring the oxygen sensors to ensure that they are working perfectly. Gas levels within the loop and the cylinders are monitored to ensure that the SE7EN+ diver has sufficient diluent gas available to reach the surface in the unlikely event of needing to “bail out” to open circuit. A three-level alarm system is there to alert the diver and buddy if something does not go according to plan. Alarms are delivered visually, by the wrist computer and the smart battery, audibly via the battery and physically, via the mouthpiece that incorporates Juergensen Marine's DIVA vibrating alert technology.