Spiral Screw ExtractorAggressive left-hand spiral design provides extra gripping power. Designed for the removal of broken studs, bolts, socket screws and fittings. Constructed of high carbon steel for strength under stressful conditions. Extractor size and recommended drill bit size are etched on each extractor. Bolt/Screw Cap.: 9/32 - 3/8 in, 1/8 in NPT, 1/8 in BSP, 8 - 10 mm; Used With: TR-88 Tap Wrench; Use Drill Size: 1/4 in; Wt.: 0.07 lb.