♦ FOR VIPER M4, SR15, SR16
♦ Include: disassemble heavier mass
♦ Full CNC machining, manganese phosphate surface treatment
♦ Recommended to use gas magazine
♦ (M3 Screw) Recommended fastening torque 1.96 N.m
♦ Please use torque wrench and threadlocker
♦ Piston bore diameter: 19mm