General purpose off-hand work. 6-8 include bushing for 1/2, 5/8, 3/4 and 1 ( for 8 wheels ) arbor holes. 10-12 x 1 1/4 includes bushing for 1 1/4, 1 and 3/4 arbors. 12-14 x 2 includes bushing for 1 1/2, 1 1/4 and 1 arbors. New improved bond, reduces dressing and is freer cutting, reducing heat.