Features and Benefits: Designed to remove broken studs, bolts, socket screws and fittings; Aggressive left hand spiral design for extra gripping power; Spiral flutes are designed to embed themselves deeper into the metal as you turn the tool, so as the fastener resistance increases, the extractor's grip increases; Extractor size and recommended drill bit size are etched on each tool; Recommended tap wrench: TR-98; use drill size: 13/32" removes bolts and screws: 5/8" - 7/8", 3/8" NPT, 3/8" BSP, 16 mm - 22 mm.