The ABN Broken Bolt Remover Small Screw Extractor Kit is designed to help you remove stubborn broken or stripped bolts, studs, and screws. The screw extraction kit includes 35 bits that are constructed of heat-treated chromium-molybdenum (carbon) steel. Each bit is precision cut into a left-handed spiral design that will extract any faulty threaded pipes, fittings, pins, and even hexagonal socket screws and bolts. Size markings are etched onto the bits and on the plastic storage case. Screw extractor bit sizes include 1/8in, 5/32in, 3/16in, 7/32in, 1/4in, 9/32in, 5/16in, 11/32in, 3/8in, 13/32in, 7/16in, 15/32in, 1/2in. Left hand cobalt drill bit sizes include 5/64in, 7/64in, 1/8in, 5/32in, 3/16in, 7/32in, 1/4in, 9/32in, 11/32in, 3/8in, 13/32in, 7/16in, 15/32in, 1/2in. Warning: This product can expose you to chemicals which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm.