Simone Giertz, a roboticist and general-purpose genius, introduces us to her latest and perhaps simplest invention: a Phillips-head screwdriver ring. This is handy, as one occasionally needs a Phillips head in one's daily adventures. It could also serve, I suppose, as an improvised weapon, as it adds a bit of spiciness to punches and backhand slaps.
Hopefully Giertz will also offer the ring with various sizes of Allen keys, as access to a common size could be helpful for some people.
Giertz notes that she shaved off the hair on her knuckles to make this video, so we should be grateful not only for her invention, but her sacrifices that she made to promote it.