Dry fire training adapter- insert into a pistol magazine to prevent the pistol slide from locking open on an empty magazine. Allows you to practice a "Tap/Rack" drill with a magazine inserted. Made around the dimensions of a 9mm Springfield Armory Hellcat, though should work with other double-stack magazines. There are 2 files included, one that has a flat top (DryFireNoTension.stl) which should be the most universal. I created a second model (DryFireTension.stl) to allow the spring in the magazine to press the adapter against the bottom of the slide- this reduces the "rattle" of the magazine.