Features and Benefits: Made from rugged, high carbon steel to handle the stress of removing bolts Extractor size and recommended drill bit size are etched on each tool for easy identification Designed to remove broken studs, bolts, socket screws and fittings Aggressive left-hand spiral design for extra gripping power Method of use: After drilling hole with either right or left-handed drill bit, (left is recommended) insert extractor, turn counter clockwise Grips into sides of drill hole and removes broken part without damaging the threaded hole Specs: Recommended tap wrench: TR-88 Use drill size: 1/4" Removes bolts and screws: 9/32" - 3/8" and 1/8" NPT, 1/8" BSP, 8mm - 10mm Carded