"I bought gearbox as a replacement gearbox for my jg gen4. The gun would fire on full-automatic when the selector was off of safe.
I bought this one with the intention of fixing the other gearbox but still having a working gun. Unfortunately, after about 3 weeks, this gearbox came down with the same problem.
I give it 2 stars because it shot hard and fast, until it malfunctioned. "