Sizes are 1/16, 3/32, 1/8, 5/32, 3/16, 7/32, 1/4, 5/16, 11/32, 3/8, 13/32, 7/16, 15/32, 1/2, 17/32, 9/16, 21/32. Bases are 20mm diameter and the collets are 70mm long.