Polarstar JACK - HPA Standard FCU Conversion Kit Multicam Holds 28 rounds

Holds 28 rounds

but not for the Action Army Hop up Chamber

Upgrade Give your hopup an upgrade boost from Airsoft Atlanta

2022 Edition - Upgraded features including locking bolt back for hopup adjustment

Fire modes include semi and full auto

Polarstar JACK - HPA Standard FCU Conversion Kit Multicam Holds 28 roundsThe Polarstar JACK HPA Standard FCU Conversion Kit. This is the full sized FCU version for easy programming. Contains everything you need internally. Works drop in with most M4 AK platforms. G&G, Elite Force, JG, and most are pretty easy to install. Watch some Youtube videos on how to put it in yourself. With the Polarstar JACK engine, all you need to complete your HPA setup is: HPA Air Tank (non SLP tan regulator is okay, Ninja, Valken, FS is good)