This is the Mares ROVER 2S 1st and 2nd Stage Scuba Diving Regulator Features: 1st stage Lightweight, sturdy and compact Piston control Dedicated place for rfid chip 2nd stage Easy-to-use purge button with dynamic hinge design Vad system with fluid dynamic deflector Mid-size Oversized purge button Rubber hose Patented design which reduces the impact of water flow onto the second stage diaphragm, thus eliminating free flows even in strong currents. Abrasion resistant and affordable, ideal for diving in warm and moderate water temperatures. The air bypass tube delivers air to the mouthpiece creating a swirling vortex with a low pressure area in the center that keeps the diaphragm down during inhalation, for very sensitive and easy breathing at all depths. Minimizes intermediate pressure drop during inhalation thus maximizing gas delivery, especially under extreme conditions. Mares ROVER 2S 1st and 2nd Stage Scuba Diving Regulator.