You own your own cylinders or sometimes rent them for local dives and want a means for safe transport. Need a way to stop those tanks from rolling back and forth in you truck bed, boat, or car trunk? 2 Tank EVA flex foam tank rack with durable poly line connectors, is a lightweight design and works great in car trunks, truck beds, and on boats. The Tank Holder will hold most tanks. A must have for the diver with personal cylinders or those who rent for local diving.