This IRWIN HANSON 536/526 Series 5-Piece Straight-Flute Screw Extractor is designed for softer materials or thin-walled pieces, specified as pipes and fittings. The design on these screw extractors extraction because it does not expand the material as it is removed. Each IRWIN screw extractor can remove both left-handed and right-handed rib parts and has the size and recommended drill bit size onto it.