They are also called "Shark Wrenches". I have seen them used backstage. A Swedish foreign student working at the local college theater had the first one I saw -- she was cute but I didn't understand a word she said. Then last spring, one of the roadguys on "Phantom" had one and knew the whole story on them. He was in England on a rock'n'roll tour and got one from the crew there. They used them for setting up scaffolding, the shark jaw could get a grip on the 2" wingnuts on cheesborough connectors [especially if you set the hole on the 3/8" allthread and spin the 'wing' from the inside], and the spanner head was good on setting lights. I forgot the Swedish manufacturer's name. I want one too.

Every 25 years I like to rebuild that 292 just for GP