The autosear, or "Glock switch", is a tiny chunk of molded plastic and/or metal which makes handguns (and AR-style rifles) fully automatic. Installed in seconds, they cost about $20. Or you can just make your own in a metal shop or with a 3D printer. The ATF is displeased by this development: "the switch is classified as a machine gun under federal law." Vice News reports on the "flood" of such guns in the U.S.—owning a switch will most certainly get you in serious trouble.
In other words, it's a gadget that turns handguns into ludicrously inaccurate, dangerous junk and they come with a free jail term. Graphic designer rules apply: if you care about your work, get a mac!