The 14-piece bolt and nut socket set is built from high quality chrome-molybdenum steel and heat treated to resist rust and corrosion for long term durability. Clear size markings on each socket aid quick identification, and all screw extractors are stored in a compact carrying bag for easy storage and access. The kit includes 13 different sizes of screw extractor sockets plus a 1/4" to 3/8" socket converter to cover most repair needs. Sizes are: 1/4", 5/16" (8 mm), 3/8" (10 mm), 10 mm, 7/16" (11 mm), 12 mm, 1/2" (13 mm), 13 mm, 9/16" (14 mm), 5/8" (16 mm), 17 mm, 11/16" (17.46 mm), 3/4" (19 mm). The reverse spiral design features an internal thread with a reverse spiral groove that bites downward to deliver maximum clamping force. The faster the socket rotates, the greater the clamping force, making it effective for clamping and removing round fasteners, nuts, bolts and screw parts. Compatibility and versatility: external hex drive sockets can be used with flat head wrenches, pliers, adjustable wrenches, hex sockets, or vise locking pliers. The 3/8" square drive sockets can be connected to socket wrenches, impact wrenches, ratchet wrenches, and pneumatic tools. Use scenarios: - Automotive repair to extract rounded or stripped bolts in engines or exhaust systems. - Home maintenance to remove stripped nuts from furniture, appliances, or shelving. - Workshop or industrial settings to free seized fasteners on power tools or equipment when using impact tools.