Long discontinued, one pair of 6" steel, hardened jaws that fit the big heavy Mechanics 646 that has the 2 3/8" center to center. hole in back. Made here in the USA these jaws are 6" Wide, 1" High, and 5/8"Thick, with hole spaced at 2 3/8" center. These come with 4 1/4-20 screws. These jaws should last the life of the vise. They will come with a Paraffin coating as a rust preventive. Shipping will be to the 50 states. Any questions, please ask me. Thanks for looking