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
The MK25 EVO first stage lets you enjoy an ultra-fast breathing response, instant delivery of air on demand, great sensitivity and extra-high airflow -- regardless of how cold the water is. This is made possible with SCUBAPRO's exclusive patented Extended Thermal Insulating System (XTIS) that fully isolates the mechanical elements of the first stage from the cold, increasing its freezing resistance 30 percent over previous versions of the MK25 without compromising breathing performance. This makes the MK25 EVO the ultimate do-it-all first stage for all water temperatures.
Air balanced flow-through piston
Chrome plated brass body
Externally adjustable intermediate pressure
Low pressure ports 5 on swivel turret, High Pressure Ports 2