AP0331/DS4 XTX40 REGULATOR DS4 A-CLAMP AP0331-1/DS4 XTX40 REGULATOR DS4 DIN Second stage - pneumatically balanced with adjustable venturi. Features heat exchanger to protect against freezing – so ideal for diving all over the world, even in the coldest waters. Right or left hand configuration. Small exhaust system fitted. Environmentally dry sealed, balanced 1st stage. No swivel turret. 4 medium pressure ports and 1 high pressure port. Finished in highly polished chrome. Oxygen compatibility kits available. 1st stage ports: 4 x 3/8” UNF & 1 x 7/16” UNF