These are extended-reach dovetail jaw sets for the Easy Chuck.
Made of nickel-plated hardened steel, they have smooth, non-marring external and internal gripping surfaces, with rounded corners to reduce the risk of injury from contact with the spinning jaws. These have longer jaws to provide an extended reach on larger projects, up to 24" in diameter for the largest set. The smallest set accommodates a straight tenon; the rest accept dovetailed tenons.
The smallest set has a 1/2" external size, a 1 1/4" internal size and a jaw length of 1 1/4". The medium set has a 1 3/8" external size, a 2" internal size and a 1 1/4" jaw length. The largest jaw set has a 3 1/2" external size, a 4 1/4" internal size and a jaw length of 1".
External and internal sizes are optimal; recommended for tenons and recesses up to 1/4" larger than the listed sizes.