This is the Cressi MC9 Compact 1st and 2nd Stage Diving Regulator Features: Balanced diaphragm (seal chamber for MC9SC) 2 outlets HP 7/16 UNF 4 outlets MP 3/8 UNF Service pressure: 300 bar (4350 psi) DIN version, 232 bar (3365 psi) Yoke version Calibration pressure: 10 Bar Brass body Electroless Nickel plated High capacity conical filter electroless nickel plated Aisi 316 removable nozzle Hyper-balancing Anti-pressure drop pneumatic spring Setting spring: stainless steel with micropeening treatment Replaceable cylinder with anti-friction and anti-corrosion properties Elastomer protector Flow rate: 4500 l/min weight: 590 gr TECHNICAL FEATURES 2ND STAGE: Downstream system Adjustable venturi effect Patented antifriction lever Big purge button Anti-scratch surface Bayonet-type cap holder with security lock Removable exhaust tee Weight without hose: 135 gr COMBINATION PERFORMANCE Average Cracking effort 6 mbar Average breathing effort 1 J/l This premiere travel regulator packs maximum performance into minimum space.A true featherweight second stage, the Compact is built from lightweight techno-polymers to eliminate jaw fatigue.Easy to pack and easy to dive, the Compact includes dive/pre-dive Venturi switchfor managing freeflow and maximizing performance at depth.