
I recently had a 'service' done on my gas grill - thoroughly cleaned everything and replaced any rusted or otherwise worn parts. I had two hex head screws that I couldn't remove with a screwdriver or regular sockets. In fact, my attempts resulted in a pair of "rounded" hex head screws. I've tried drilling a hole in the center of a screw and prying it out with a screw extractor. Not only did it go wrong, but the extractor broke one of the screws. I was able to remove both screws with surprising ease. The visible part of the heads have protrusions that catch the flat (or not so) side of the bolt or nut. The bushings taper inward and grip "roundedโ hex bolts surprisingly well. That seems like a good design, although it means they're only good for loosening up. Of course, as soon as I loosen the snap, I replace it with a good one. The caveat is that they work best with hex bolts or screws. They don't help much with "out" Phillips screws. (The world would be a better place with Robertson screws.) I'm glad I don't need them very often, but when I do, they save me a lot of time (and swearing).