ARCHWICK Carbine Kit B&T Air USW G-17

This is the USW G-17 from ARCHWICK. It's a polymer conversion kit for airsoft guns, compatible with Glock 17 type airsoft guns from various manufacturers. (We have confirmed compatibility with BATON airsoft guns.)
After purchasing it new, I tested attaching and detaching it as mentioned above, and then stored it indoors. It has not been used in airsoft games or similar activities.
*Non-smoker.
*No pets.