he Polarstar JACK V2 M4 Engine - HPA Standard FCU Conversion Kit. This is the full sized FCU version for easy programming. Fits in most M4 and M16 airsoft guns for a full air line HPA engine conversion. Contains everything you need internally. Works drop-in with most M4 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)
- Air line regulator (non-SLP) - Wolverine, Valken, Ninja are all good
- Air line from the regulator to the gun/engine
- 7.4v 250mah battery to power the engine (plus LiPo charger)