This will hold your magazine follower down, allowing you to fire a GBB pistol (or rifle) with gas but no BBs. Great for training or having fun without putting dents in the walls. The design has been revised since Thingiverse removed the original file (politics below). It now sits even more securely on the follower now I understand almost all double stack followers slope in the same direction. The main picture is from SirLanceOlong's make of my original file. I would ask him if he minds me using his picture but he is no longer registered on Thingiverse, hopefully he will get in contact if he objects. Thingiverse took this Thing down citing copyright infringement on behalf of Glock. Glock does not produce airsoft parts, and certainly does not make one of these magazine follower stops. This is my own design (obviously) and I believe the infringement claim was made by a malicious third party. This seems to have affected at least 4 other users on Thingiverse that I can see, none of which I can tell had infringed on any product that Glock make (most of which I am quite familiar with). Thingiverse/Makerbot have yet to respond to any of my emails after a week (now 2 months) so I am reposting this Thing for the benefit of all.This tiny piece of plastic is a stupidly quick print, and incredibly useful. In order to make the most of all the super tiny features and angles I've printed the black one you see in the gallery at 0.05mm (!) layer height. No supports, most slicers will give this 100% infill due to the size. I really recommend using glue and low bed temps to minimise warping of the very tiny features.