“GBB” type, flat hopup rubber, 4 hardness set (50°/60°/70°/80°)
Initially designed for the TAC-41 “GBB” hopup, this hopup rubber can fit inside most of airsoft guns using “GBB” hopup rubber.
Transparent silicone for easier installation, this kit includes 4 hardness:
– blue color, 50°
– green color, 60°
– yellow color, 70°
– red color, 80°
