Designed to remove broken screws, bolts, studs and fittings. Tapered left hand spiral design for extra gripping power, grips screw firmly. Bolt remover that remove broken screws, whether working on wood or metal, are ideal for construction, automotive, home DIY projects or for industrial use. Chrome Alloy-Steel construction for strength and longevity. 5-Piece Set includes: #1, #2, #3, #4, #5 spiral screw extractors. See description for drill sizes and screw diameters Screw Extractors are designed to remove broken screws, bolts and studs. These screw extractors are constructed out of Chrome Alloy-Steel for strength and longevity. They featured a tapered left hand spiral flute to grip the screw firmly. The polished body and sandblasted flute prevents rust.