Compact, air-balanced diaphragm design, MK11 EVO delivers top performance and reliability Forged brass body comes with metal fins to improve thermal exchange plus plastic bumpers to prevent scratching Two high pressure ports are set on a 15-degree angle for convenient hose routing. Four high-flow low pressure ports increase airflow while maximizing hose routing options. Innovative double spring layout increases performance while contributing to overall compactness C370 second stage's air-balanced valve smoothes out the inhalation effort at varying depths and supply pressures Compact, rugged fiberglass-reinforced nylon C370 casing takes up little space in a dive bag User controls include a diver-adjustable inhalation effort knob and coaxial dive/pre-dive lever Large purge button is easy to activate, even wearing thick gloves Super-flow hose features an oversized bore that allows more air to flow on each inhalation