Straight Flute Screw Extractor, Designed For Softer Materials Or Thin Walled Pieces Such As Pipes & Fittings, Design Eases Extraction Because It Does Not Expand The Material As You Remove It, Removes Both Left-Hand & Right-Hand Threaded Parts, Removes Bolts & Screws 1/2inch - 9/16inch & 1/4inch NPT, 12 mm-14 mm, 1/4inch BSP, Use 5/16inch Drill Bit.