Summary

The Hand clamp is shown assembled with the following:-
6mm x 120mm Stud, 1 x 6mm Nyloc Nut, 1x6mm coupler (or wingnut), 2 x 4mm Rivetnuts and 1 x 4mm x 16mm bolt. Also shown is a 6mm x 90mm Bolt instead of the stud with an elastic band. The maximum size to fit in the jaws is just over 40mm.

The smaller of the other two clamps also used 6mm x 120mm Studs, 4 x 6mm half nuts. With 6mm couplers. The depth of the jaw is about 32mm.

The other clamp used 8mm x 450mm Studs, 4 x 8mm half nuts. With 8mm couplers.
The depth of the jaw is about 35mm.