If you plunge into the sea to ogle exotic wildlife, why not stay a while—and get an even closer view? Cave-diving engineer Bill Stone [see “Journey from the Center of the Earth,” February 2007] makes that possible with the most user-friendly version yet of a rebreather, a device that recycles your exhaled air, removes carbon dioxide, and adds oxygen. (A scuba device quickly burns through tanks of fresh air.)

On a typical dive, the Poseidon Discovery lets divers stay underwater at least three times as long as scuba gear can, and since you don’t exhale into the water, you don’t create bubbles or noise that can scare off fish.

Careful Computer

A computer indicates how many minutes of air you have left.

Lip Service

The mouthpiece vibrates and blinks to alert you of a malfunction.

Military and advanced divers have used rebreathers for decades, but they’re pricey rigs (about $10,000) that require extensive training on how to manually mix gases in case the gear fails. Stone’s recreational model automates the safety system with built-in computers that check all components pre-dive, plus two oxygen sensors that monitor the gas mix. If the system spots an air-recycling malfunction, the mouthpiece vibrates and blinks an alert. Just flip its lever to inhale from a small fresh-air tank and return safely to the surface.

See more innovative diving products here.

Poseidon Discovery

In our April issue, we feature a high-tech ocean-diving system [left] that lets you stay underwater for hours at a time. What to do while you’re down there? Try playing with the following four gadgets for the great deep sea.


Just slip this eight-speed scooter between your knees to swim around without moving a muscle. Unlike other diver propulsion vehicles, which pull you through the water as you hang on, it leaves your hands free. $2,500;

Scubapro UWATEC Galileo Sol

This dive computer is the first to keep tabs on your heart rate. When combined with traditional stats like tank pressure, depth, and breathing rate, it gives the computer better accuracy in determining how long you can stay underwater. $1,980;

Aqualung Slingshot

On these ultra-efficient flippers, silicone straps between the footpocket and blade capture energy from the downstroke of the kick and immediately snap back. This delivers increased propulsion while reducing fatigue. $219;

Sea and Sea DX-1G

This SLR-style underwater camera gives you 10 megapixels (and even shoots in RAW) at depths up to 180 feet. Back on dry land, pop it out of the waterproof housing and you can use it like a regular camera. $1,000;