This video demonstrates the use of Submersible System´s Spare Air Pack. Spare Air comes in two different sizes: 1.7 Cubic Feet and 3.0 Cubic Feet. The 1.7 CF has roughly 30 breaths at the surface while the 3.0 CF bottle has approximately 57 breaths at the surface. These units are an alternative to a pony bottle system while being much smaller and only weighing about 2 pounds. They are great for traveling and are the answer for out-of-air emergencies.