Premium Material: Made of high-hardness Chrome-molybdenum steel with anti-rust electroplated surface for high torsional strength and ensuring long-lasting performance. 3/4 Flute Specification: 1#: 3 flute, M4, 6#; 2#: 3 flute, M5, 8-10#; 3#: 3 flute, M6, 12#-1/4; 4#: 3 flute, M8, 5/16"; 5#: 3 flute, M10, 3/8"; 6#: 4 flute, M12, 1/2"; 7#: 4 flute, M14, 9/16"; 8#: 4 flute, M16, 5/8";9#:4 flute, M18-20, 3/4"; 10#: 4 flute, M22, 7/8". Precision Size: There are 10 sizes of tap extractors, 1#-5# are 3 flutes, and 6#-10# are 4 flutes, featuring the groove structure, these tap extractors can grab broken screw taps speedily. The square head is compatible with a tap wrench or adjustable wrench. Efficient Extraction: Select the appropriate tap extractor and insert it into the tap's groove. Then, using a tap wrench or adjustable wrench, unscrew in the opposite direction. The result will be a newly restored tap thread. Wide Application: The tap extractor is specially designed for fast grasping and easy removal of stripped, rusted, broken, or corroded screw taps. It's an essential tool for industrial and home repair work.