13 pc. Carbide tipped hole saw set contains: one each: 3/4,7/8, 1-1/8, 1-3/8, 1-1/2, 1-3/4, 2, 2-1/4, 2-1/2 one 1/4″ round shank arbor for hole saw sizes 9/16 to 1-3/16 (1/2-20 thread) one 7/16 hex shank arbor for hole saw sizes 9/16 to 1-3/16 (1/2-20 thread) one 7/16 hex shank arbor for hole saw sizes 1-1/4 to 6 (5/8-18 thread) one extension special tooth design for very fast hole saw cutting ground and set teeth help to cut materials that bi-metal saws will not cut 3 teeth per inch creates a wider gullet for better chip clearance and faster cutting cuts trough acoustic tile, countertops, drywall, fiberboard, fiberglass, plaster, plastic, nail-free wood