For loosening a broken stud or worn screw/nut.; Tapered twist profile strengthens extraction.; Not to be used with an air/impact wrench.; Application: Hex 12mm: 3mm, 1/8″, 4mm, 3/16″, 5mm, 5.5mm, 6mm, 1/4″, 8mm, 3/8″, 10mm; Hex 16mm: 11mm, 12mm, 1/2″, 14mm; Stock Ref. No. 9CL-9103722