 It is claimed to let a scuba diver or swim much faster (250%) than with swimfins for the same amount of bodily effort, if used correctly, and being not motorized, it makes no motor noise to be heard by hostile hydrophones, but noise would occur if the front wings are allowed to hit the diver's hips at end of upstroke.It works somewhat like a penguin's or turtle's side-mounted front flippers.Its estimated cost is less than $500.