For Marui G17 Gas BlowBack Pistol - 6061 Aluminum material with CNC machined - Ultra lightweight design - Durable construction prevents flexing and warping under hard use - Provide stable and smooth blowback cycling - Perfect Fit with COWCOW CCT-TMHC-054 piston head and CCT-TMG-042 & 043 loading nozzle - Compatible with TM original piston head