High speed, heat resistant Carbide Steel teeth welded to a durable alloy backing and capExceptionally strong, safe, and shatter resistant.Includes:(15) Holesaws: 3/4, 7/8, 1 1/8, 1 3/8, 1 1/2, 1 3/4, 2, 2 1/4, 2 1/2, 3, 3 1/4, 3 5/8, 3 3/4, 4 1/4, 4 1/2 inA1E ArborA4E ArborA2E Quick Hitch ArborA12 Arbor AdapterA5 Arbor Extension