I recently bought a used S&W SD40VE. In the box was an old "ATF Youth Handgun Safety Act Notice" brochure. When I picked it up I notice it was heavier than it should be for just a paper brochure and when I flipped it over I found a metal disk with 2 prongs that looks like some kind of key or tool (see images). It has a small hole it it like it is supposed to be attached to a keychain. Does anyone know what is it, what it's for, and why it would be taped to the back of this ATF brochure in my retail gun box? Obviously, I not assuming anyone can get into the mind of the person who taped it there...I'm just hoping someone can shed some light on what it is for.
