8 pc. Hole saw set contains: one each: 7/8″, 1-1/8″, 1-3/8″, 1-3/4″, 2″ 2-1/2″ 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) positive rake teeth provides better chip clearance 1 1/2″ cutting depth will cut through a 2 x 4 variable pitch teeth reduces friction and heat expanded gullets allow for faster cutting and increased blade life better tooth match for better chip clearance and smoother cutting reinforced tooth flank makes teeth stronger for longer life and resistance to tooth strippage.