TTI AIRSOFT Infinity One Piece Full CNC TDC Hop Up Chamber-for SIG AIR M17/M18TDC Hop Up Solution for SIG AIR VFC P320 M17, M18 & X Carry GBB Pistol Infinity One Piece TDC Hop Chamber Adjustable TDC with VFC Guide Rod Adjustment Hop Design Fixation Screw to Secure Hop Chamber to Frame Wrap Around Hop up Bucking Design C Clip with Screw Improved Accuracy and Shooting Stability Improved Inner Barrel Fixing Pin, Compatible with Marui, PDI, Unicorn Inner Barrels Allows Installation of Marui Pistol Spec. Hop Up Buckings Improved