Cressi AC25g Compact RegulatorAC25g Compact Regulator The AC25 is the third generation of Cressi's IP adjustable balanced piston first stage. It features two 7 16" UNF threaded high pressure ports and five 3 8" UNF threaded low pressure ports. 4 low pressure ports are located on a rotating turret that ensures that regulator and instrument connections are always in the right position. The fifth port is a co axial hi flow port and is located at the top of the turret. The rotating