13-piece 3/8 inch drive bolt and nut remover set with easy-to-read markings: 6.35mm (1/4"), 8mm (5/16"), 9.5mm (3/8"), 10mm, 11mm (7/16"), 12mm, 12.7mm (1/2"), 13mm, 14mm (9/16"), 16mm (5/8"), 17mm, 17.5mm (11/16"), 19mm (3/4"). Designed to meet a wide range of removal needs for stripped bolts and damaged nuts. Made of high-carbon steel with a hexagonal spiral design for high hardness and improved grip. Heat-treated (high-temperature quenching) to resist slipping and breaking under load. Wide range of uses: precision internal thread design enables easy removal of damaged bolts, nuts and screws in household appliances, automotive repairs and industrial instruments, even if they are stripped, rusted or frozen. 6-Point Spiral Grip: each section features six grip points and an internal spiral design to maximize grip and torque when prying off damaged, corroded or coated fasteners, including nuts, bolts, studs and hex screws. 3/8" Drive: compatible with hand and power tools that use a 3/8" drive, including impact wrenches, pneumatic ratchets and breaker bars, for rusted, stripped or frozen fasteners.