This type of first stage SCUBAPRO regulator is the benchmark of simplicity and reliability.

The piston is the only moving part in this low maintenance first stage. Before the tank valve is opened, the piston is down in the chamber and the piston is in the open phase. When pressurized, the intermediate pressure air flows to the piston head through the piston cavity to thrust the piston against the spring and close the valve. When inhalation begins, the pressure is revived behind the piston head and the spring reopens the piston allowing the air to flow.

This cycle is repeated consistently hundreds of times during a dive, opening and closing one time for each breath.

This first stage, originally designed more than 40 years ago, is a true classic and remains virtually unchanged. It equips most dive schools throughout the world, successfully working in a variety of conditions.

The four low pressure ports and the high pressure port allow ergonomic hose configuration.

Also available in a DIN configuration.

Diaphragm-based first stages, by virtue of their environmentally sealed design, have been longtime favorites of cold water divers and those working in water containing a high degree of suspended particles, silt, or other contaminating materials.

Unfortunately, conventional diaphragm first stages are often bulky, more prone to high pressure seat failure, and seldom deliver the response time or performance characteristics of a high-quality piston design. That's where SCUBAPRO stepped in. Our balanced-diaphragm technology incorporates a pneumatically-balanced, high pressure seat design that withstands delamination along with a short-throw lifting pin that reduces mechanical drag. The result is a first stage system that responds to extremely fast flow requests from the second stage.

Furthermore, SCUBAPRO developed a hardened aerodynamic stainless steel high pressure poppet that seals against a softer high pressure replaceable orifice. This inverted seat and orifice technology, together with a patented seat guide, enhances flow characteristics. This over balancing feature has also been applied to these first stages resulting in a regulator system that delivers unprecedented performance and reliability. The MK16 features 2 HFPs (high flow ports) to feed the main and octopus second stages.

The MK16 is an over-balanced diaphragm first stages.

Also available in a DIN configuration.

In the case of SCUBAPRO's premier-performance Air-Balanced Flow-Through Piston technology, this proprietary design allows air to flow directly through the hollow interior of the piston shaft, rather than diverting incoming high pressure around the piston and the seating mechanism as in conventional piston designs. This technology delivers two significant performance advantages.

First, because the piston is unaffected by changes in pressure, the SCUBAPRO regulator can deliver a consistent air flow to the second stage regardless of changes in tank pressure.

Second, because the flow-through piston design creates a more direct air path through a bigger bore air passage, this SCUBAPRO regulator is able to deliver significantly higher quantities of air on demand.

Independent and government laboratory tests have repeatedly shown the real-world performance advantages of SCUBAPRO's patented flow-through technology.

SCUBAPRO engineers have designed a variable shaft diameter piston that out performs standard cylindrical pistons. By exposing just a small surface area of the modified piston shaft to the incoming high pressure, the piston reacts to boost the intermediate pressure as the pressure in the cylinder decreases. Consequently, instead of an increase of breathing resistance towards the end of the dive (as in standard first stage designs) or no change throughout the dive (as in balanced first stage design), the MK25 makes breathing easier as the dive progresses. This unique feature is called over-balancing.

Also available in DIN configuration.