Will says: “I thought this sounded too good to be true when my brother told me about it, but once I used it I quickly found it to be the real deal. It takes a bit of getting used to — you have to grab it towards the front — but the way it performs makes it a small hurdle. This thing has teeth that are fierce so it doesn’t slip, and its jaws self-size with no dialing.”
We used something similar (from Husky) to remove a sheared bolt a while back, but the mechanism in these looks pretty interesting.
The ViperGrip [IDL Tools]