Adapter comes with GTP9 magazine installed.
This is a custom designed laser sintered nylon adapter that allows you to use HPA (high pressure air) and M4 AEG magazines on your Gtp airsoft GBB pistol or SMC9 GBBR. To use it you will also need an M4 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 temperature. We recommend that you run you pistol near this pressure and do not exceed 140 psi. Keep in mind that higher pressures can cause excessive wear and damage to the internal components of your airsoft pistol.
I designed this adapter to even the playing field when playing airsoft with a pistol as a primary against AEGs with hi-cap mags.