This 5-piece screw extractor set is intended for removing snapped or broken bolts and screws from components such as manifolds, castings and heads. It provides a practical method for extracting damaged fixings when conventional tools can no longer grip them.Features Removes broken bolts and screws from damaged or seized fixings. Suitable for use on manifolds, castings, heads and similar components. Tapered extractor design suits a range of fixing sizes. Reverse-threaded shafts bite into the fixing and remove it in one action. For use with power drills operating in reverse. Specifications 5-piece extractor set. Construction: hardened steel. Recommended pilot hole: around 50% of the screw or bolt diameter. Size range 1: 1/8" - 1/4" / M3 - M6. Size range 2: 1/4" - 5/16" / M6 - M8. Size range 3: 5/16" - 7/16" / M8 - M11. Size range 4: 7/16" - 9/16" / M11 - M14. Size range 5: 9/16" - 3/4" / M14 - M18. Cross-Reference OEM Part Numbers Part number: 00-690.