You cannot breathe directly out of a scuba tank because of the high pressure. A regulator reduces pressure to safe a level that can be inhaled by the diver. A diving regulator has two parts: the First Stage reduces the tank pressure and connects it to the Second Stage which contains the mouthpiece for breathing
MK11 diaphragm first stage has the same structure as MK17 but without a dry chamber and it is the perfect choice for the recreational diver who wants the advantage of a diaphragm first stage for use in temperate waters.
Chrome plated brass body
Cold water Anti-Freeze protection & Dry chamber