High speed, heat resistant Carbide Steel teeth welded to a durable alloy backing and cap Exceptionally strong, safe, and shatter resistant.Includes:(6) Holesaws: 3/4 in, 7/8 in, 1 1/8 in, 1 1/2 in, 1 3/4 in, 2 1/4 in(1) A1E Extended Length Arbor(1) A2E Extended Length Quick Hitch Arbor(1) A12 Arbor Adapter(1) A014CE Extra Length HSS Pilot Drill