A 13 piece set of 3/8" drive impact sockets for extracting damaged bolts. Spiral cut teeth provide a positive grip to remove rounded or damaged bolts & nuts. Can also be used on screw heads and studs. Will fit head sizes: 1/4", 5/16", 3/8", 10mm, 7/16", 12mm, 1/2", 13mm, 9/16", 5/8", 17mm, 11/16" and 3/4" 3/8" Drive Manufactured from hardened Chromium Molybdenum Steel for strength with a black manganese phosphate finish for protection HRC 48-52