These are standard 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.
Two sizes are available. The small set (supplied with the chuck) is suitable for work up to 6" in diameter. It has an external size of 1 3/8", an internal size of 2", and a jaw length of 7/16". The larger jaw set accommodates projects up to 12" in diameter. It has an external size of 2 3/8", an internal size of 3", and a jaw length of 7/16".
External and internal sizes are optimal; recommended for tenons and recesses up to 1/4" larger than the listed sizes.