How does tankless diving work? It's a form of surface-supplied air diving that does not involve a scuba tank (thus, tankless). So where does the air come from, you ask? It is delivered by a compressor drawing air from the surface and pressurizing it so that it will actually go down the hose (otherwise, due to pressure change underwater you would not be able to suck air through the hose to more than about 2-3 feet!) Our battery-powered compressors are manufactured in our factory in Davie, Florida