Safety back-up air supply Having a safety back-up air supply has many advantages over a standard alternate air source. The most obvious is that it is a separate air supply and allows self rescue in an emergency out of air situation. We are taught to stay with our buddy so that in case of an emergency they are right there ready to help us. Next time you make a dive count the times your buddy is further then arms length from you. You will be surprised that they are much further away more often then you may think. Spare-air gives you a major advantage over an alternate air source when an emergency arises. Having something to breathe from while you are swimming to your buddy, and then, getting their attention while they have their head in a hole watching a lobster can take several breaths or more of air. Submersible Systems Original inventors and manufacturers of the patented Spare Air, have been in business for over 40 years and sold over 350,000 units. Spare Air and Heed units are made in the USA. 3 cu ft / 85 liters 3000 PSI (200 bars) 3.0 cu. Ft. (85 liter) of outstanding, refillable backup air system, small and easy to use What is the recommended depth? The Spare Air model is designed for recreational diving limits of less than 100 feet. Spare Air A skydiver wears a reserve parachute, a SCUBA diver should have a reserve breathing system. For 40 years we’ve supplied divers with the smallest, most-compact redundant system available for out-of-air-emergencies. The patented SPARE AIR should be a standard piece of SCUBA diving equipment for the safety minded diver. In an out-of-air-emergency, why would you trust your life to anything else? Submersible Systems Cylinder Volume Depth Spare Air