【High-Quality】Forged from chrome vanadium steel, it is stronger than tool steel, bolt extractors have oxide surface provides greater strength and durability and prevents corrosion. 【Tight Grip and Bit】 The special internal thread design provides excellent torque and can be used to rotate fasteners with deep nails. The inner non-smooth concave wall helps to grasp the stubborn nut, and the more the rotation, the tighter the grip, the easier it will not break or slip 【Dimensions】Include 13pc 3/8 inch drive bolt & nut remover comes with 1/4"(6.35mm), 5/16"(8mm), 3/8”(9.5mm), 10mm, 7/16”(11mm), 12mm, 1/2”(12.7mm), 13mm, 9/16”(14mm), 5/8”(16mm), 17mm, 11/16”(17.5mm), 3/4”(19mm). 【Works With Most Tools】with a 3/8” square drive for use with hand ratchets, impact wrenches & air ratchets; hexagonal flats for use with flat wrench, pliers,adjustable wrench, sockets.