1Excellent Torque: The unique plum shaped female thread design provides excellent torque and can be used to rotate fasteners with deep bolts. 2Tight Grip: The uneven internal wall help support the hard nut, and the more you rotate it, the tighter the grip will be and the easier it will be to not break or slide. Spiral cutting teeth provide a reliable grip to remove round or damaged bolts. 313 Pieces: The full size includs 1/4in, 5/16in(8mm), 3/8in,10mm, 7/16in(11mm), 12mm,1/2in, 13mm, 9/16in(14mm), 5/8in(16mm), 17mm, 11/16in, 3/4in(19mm). 4Professional and Functional: Nut extractor socket is professional and functional, you can remove damaged, broken, rusty, rounded off bolts, nuts and screws. 5Rustproof: The surface of each nut extractor is coated painting process, this more complex process can make our nut removers more resistant to wear and tear, and will not rust so easily after a long time of use.13 x Bolt Nut Remover1 x Storage Box