Submersible System Spare Air Model 170, 300 and 300 Nitrox Package Kit 1.7-3.0 cu ftSpare Air is the smallest redundant scuba system available with enough air to get you to the surface in an out of air emergency. The patented Spare Air should be a standard piece of scuba diving equipment for the safety minded diver. Explore the wealth of information about our product and diving in general. Our goal is to convince you to save your own life in an out of air emergency. The answer for out of air emergencies The smallest portable air