If you look at the third picture down, you can see the piece of metal that is forced down between the jaws of the puller to prevent the jaws from slipping.

I had no trouble using the "borrowed" one I tried.

A gun in the hand is better than a cop on the phone.

98 Passport 33's, Supercharged, Calmini Bumper, rockbars, diff drops, Teralows, 4.77's, Aussie and ARB lockers, Safari snorkel, Optima red top.