SHS CNC Aluminium One-Piece Hop Up Chamber Set For V2 Gearbox Version 2 M4 M16 Series AEG Rifles AirsoftSHS CNC 7075 Aluminium One Piece Hop Up Chamber Set for M Series AEG Made out of CNC 7075 Aluminium. This One Piece Metal Chamber Set is more durable and accurate in feeding BB. Improves Firmness of the chamber stabilizes the muzzle velocity. Fits most metal bodies (except KWA metal body). Fit tightly to the barrel base to keep the chamber being centered. Suitable for M4 M16 series version 2 AEG gearbox . Compatible with all Tokyo Marui M4 M16 series