Features: -designed to remove broken studs, bolts, socket screws and fittings for high torque applications. -Aggressive left hand spiral design for extra gripping power. -Hex head size: 1/2". -bolt diameter: #12. Number of bits: -5+. unit material: -steel. Use material: -metal. Product type: -driver bits. Use: -extractors. Dimensions: overall product weight: -04 pounds.