This is the ScubaPro MK2 EVO 1st Stage Scuba Diving Regulator Features: Flow-By Piston Design Marine Grade Chromed Brass Body and Components Compact and Lightweight Weight: 24.9 oz. (706 g) 4 LP Ports 1 HP Port Fail-Safe Downstream Valve EVO: Means Evolution, Revolutionizing Existing Technologies to Higher Performance High Performance in Warm and Cold Water Meets New EN250-2014 Requirements CE Approved for 3360psi (230 bars) in Cold Water Conditions Increased Cold Water Efficiency by 50% Over Previous MK2 Regulator The Mark 2 EVO DIN is the best example of bulletproof reliability and trouble-free, minimum maintenance regulators. The classic downstream piston configuration is the simplest mechanism that exists to control the pressure drop from a tank to feed the second stage. The classic downstream valve is the first choice of diving centers and rental facilities worldwide for warm and moderate water temperatures.