PPS (SHS advanced airsoft) M4 Metal Hopup Chamber - SHS TT0083 - Comes with all the internal parts needed to operate (adjustment wheel, hopup arm, nub, etc.). CNC Easton 7075 Aluminum construction made. Surface treated for anti-oxidation. Newly redesigned in March 2015 to improve the original SHS model to prevent loosening. Very durable and accurate in its bb feeding system. Replaces your original hop up chamber with an easy install.For use with any M4 style AEG airsoft gun.