General description Comprehensive 49pc master extractor set, including Chrome Molybdenum screw, bolt, stud, and nut extractors. This set features left-handed HSS drill bits for drilling pilot holes (a reversible drill is required) and spiral flute extractors for use with bolts/fasteners requiring less torque. Multi-spline extractors are included for higher torque or restricted access, along with 3/8" square drive reverse spiral bolt extractors designed for maximum grip of bolts and nuts. The set comes with a 3/8" to 1/4" square drive adaptor and is supplied in a storage case. Technical specifications Model No.: AK8149 Contents: Multi-Spline Extractors; sizes include 1/8", 5/32", 3/16", 7/32", 1/4", 9/32", 5/16", 11/32", 3/8", 13/32", 7/16", 15/32", 1/2"; Reverse Spiral Bolt Extractors; sizes include 1/4", 5/16" (8mm), 3/8", 10mm, 7/16" (11mm), 12mm, 1/2", 13mm, 9/16" (14mm), 5/8" (16mm), 17mm, 11/16", 3/4" (19mm); Left-Hand HSS Drill Bits; sizes include 5/64", 7/64", 1/8", 5/32",