Ice Hardened cryogenically treated for longer life. Optimized tooth form for faster cutting. Wide, angled and offset slots for easy plug access. Bi-metal construction with 8% cobalt for increased wear resistance. For use with steel, non-ferrous metals, wood, plastic. Includes 1 each: 7/8", 3/4", 1", 1-1/8", 1-1/2" hole saws, 1/8" hex key, hole saw arbor adapter, hole saw arbor spacer, 3/8" small thread quick change arbor, 1/4" x 3-1/2" high speed steel pilot bit.