VFC MP5 Hopup Arm and Nub V2 vipertech (helps to close receivers that

(helps to close receivers that previously needed to remove the pivot pin)

Special chamfering of nozzle to give the best seal to the inlet valve

I would highly recommend utilizing HPA with this recoil spring as I have done zero testing with regular propane gas

The height may need slight adjustment to get the correct height

I would encourage you to complete this piston by buying Bavtechs Brass piston to complete this

VFC MP5 Hopup Arm and Nub V2 vipertech (helps to close receivers thatThis arm provides more consistent hopup tension on the bucking for more consistent BB backspin. 7075 anodized aluminum. Rubber Nub. This new version is CNC machined rather than 3d printed. This hopup arm allows for the use of a rubber nub which will greatly improve your hopup consistency!