NOT GLOCK FACTORY, This plug is designed to close the open cavity at the bottom of the grip, preventing debris from entering and reaching the trigger assembly and firing pin. Eliminates possible snagging while drawing. Used world wide, fit may vary between models. Select correct plug for your model.
I like to keep a clean gun. Not only does my G21 get cleaned every time it's fired, but I keep a regular main't schedule that includes field strip, cleaning, lube, and inspection.
I installed one of these about two years ago on my G21 because I thought it would help keep dirt/debris out of the weapon. About a week ago I read an article saying that these kind of plugs actual keep dirt/debris IN the weapon. I took mine out just to check. I could not believe all of the junk and gunk that had collected in this grip plug. It was nasty. Instead of keeping dirt out, this plug actually kept dirt from falling out of weapon and trapped it inside my gun.
Plug went in the trash and the gun got cleaned. If Glock wanted that hole plugged up, they would have plugged it.