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. Automatically calibrated 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 VPT© Battery, audibly via the VPT© Battery and physically, via the mouthpiece that incorporates Juergensen Marine DIVA vibrating alert technology.

Versatile Performance Technology
Straight out of the box, the Poseidon SE7EN can operate at any depth down to 100M / 330FT. Poseidon’s Versatile Performance Technology© (VPT©) enables you to select the performance level best-suited to your dive experience and certification. Just choose the Poseidon VPT© Battery that suits your needs, insert your battery and the Poseidon SE7EN will perform within your dive comfort zone. The great advantage of this technology is that, as your diving experience grows, the Poseidon SE7EN can grow with you by upgrading your battery. It’s that simple.

Battery 40M (Green) – Depth limit of 40M / 130FT and decompression disabled. For the Recreational Rebreather Diver.

Battery Deep (Black) – Depth limit of 154M / 500FT with decompression and normoxic trimix enabled. For the highly experienced Rebreather Diver who knows no limits.

G7 Inside
Generation 7 electronics open up endless possibilities for interaction, accessories and apps. Entirely new internal hardware driven by a new generation of firmware makes the SE7EN faster, flexible and reliable in any diving environment.

Dive Management System
Enjoy enhanced interaction with your rebreather. The upgraded configuration tool interacts with your POSEIDON SE7EN via Bluetooth, allowing you to make configuration changes in moments. See your dive logs in far greater detail and much more. Better still, it’s now Mac compatible!

Bluetooth Connectivity
Download your dive logs in seconds, update your settings and interact effortlessly with your POSEIDON SE7EN, all using Bluetooth.

Recreational or 100m Technical Rebreather
The POSEIDON SE7EN can be whatever you want it to be! You can use the SE7EN as a Recreational Rebreather or as a 100M-rated Technical Rebreather; it’s your choice! Poseidon’s industry-leading upgrades give you the ultimate recreational and technical rebreather flexibility.

Enhanced Service & Support
Poseidon already has class-leading reliability and technical support, but the POSEIDON SE7EN makes service and support even easier and more convenient. Automatic dive log downloads to support via Bluetooth, combined with detachable displays and sensors mean that support is even faster and more convenient than before!

Upgraded Mouthpiece
The best rebreather mouthpiece just got even better! A new system keeps the bailout valve locked in place in closed or open circuit, while still enabling simple switches from closed to open circuit.

Protective, desirable and functional in equal measures, the cover on the Poseidon SE7EN has a built-in handle and trim weight system, along with grab and lighting rails.



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 Performance 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!






A Rebreather is a diving time machine and great for:

• Getting close to marine life – Rebreathers don’t create bubbles or noise, making you a natural part of the underwater environment.

• Exploring 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!

• 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.

• Diving in comfort – Rebreathers circulate warm, humid gas at ambient pressure, so it’s just like breathing above surface!

How a Rebreather works:

A rebreather system circulates breathing gas around the diver allowing them to “re-breathe” their gas, 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! Click on the instruction movie.

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.

Dive longer, more safely, and closer to wildlife.


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