Comprehensive 49pc master extractor set, including Chrome Molybdenum screw, bolt, stud and nut extractors. Features left-handed HSS drill bits, used to drill pilot holes (reversible drill is required), which often extract the fasteners/bolts themselves. Spiral flute extractors for use with bolts/fasteners requiring less torque. Multi-spline extractors when higher torque or restricted access is required and 3/8"sq drive reverse spiral bolt extractors designed for maximum grip of bolt and nuts. Includes a 3/8" to 1/4"sq drive adaptor. Supplied in storage case.