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°
 
Please Note
When buying parts from Longbow BB Ltd, you confirm you have the required ability to install and tech your airsoft replica as required. 
Longbow BB Ltd do offer a paid for service option for us to look at your rifle and try to solve any issues you maybe having. 
We need to manage your expectations as we (Longbow BB Ltd) are unable to provide extensive hours of tech advice for parts purchased that have been installed by yourself. 
All parts are inspected before dispatch to ensure product quality.