Primary Airsoft G-Series/AAP-01 HPA MP5 Angled AdapterThis is a custom designed laser sintered nylon adapter that allows you to use HPA (high pressure air) and Echo1 Cyma MP5 AEG magazines on your G series airsoft pistol as well as the Action Army AAP01. To use it you will also need an MP5 AEG magazine, paintball tank with low pressure regulator (0 140) psi, a hose with a Foster (polarstar) quick disconnect and of course bbs. The normal operating pressure for green gas is roughly 120 psi depending on the