Ice Hardened™ cryogenically treated for up to 50% longer life. Optimized tooth form for up to 2X faster cutting. Wide, angled & offset slots for easy plug access. Bi-metal construction with 8% cobalt for increased wear resistance. Room for Additional Hole Saw and Arbor Storage. Storage space for one (1) 12" extension or two (2) 6" extensions. Includes; Thirteen (13) Hole Saws: 3/4", 7/8", 1-1/8", 1-3/8", 1-1/2", 1-3/4", 2-1/4", 2-5/8", 3", 3-1/2", 4", 4-1/4", 4-1/2". Two (2) Arbors with Pilot Bits: 49-56-7010, 49-56-9100. Three (3) Additional Pilot Bits: 49-56-8010. One (1) Adapter: 49-56-6560. One (1) Spacer: 49-67-0120.