J...
Review confirmed by purchase 
I don't know where this good opinion comes from. The front lens is screwed in crooked; looking through the collimator, you can see protruding parts in the center. I didn't even mount it on the weapon, I sent it back. I have a collimator of this size from an English company, it's twice as expensive but five times better quality. Maybe it would be good for kids' airsoft toys with plastic pellets. For a real gun, the risk is that after a shot, the pieces of glass will hit me in the eye.
