Scubapro Regulator Mk2 Evo 1st StageSCUBAPROs classic MK2 EVO, the only downstream piston style first stage with internal components specifically designed to resist freezing in extreme cold water conditions, this regulator combo is affordable and durable while delivering smooth and reliable breathing performance. Features Technopolymer plastic barrel with a metal thread and a balanced valve helps save weight and provides a surface that ice crystals can't grab onto when diving in extreme