For Interchangeable Pilots. Includes: 13 Counterbores: (1/4" thru 1" by 16ths) and 26 Pilots: (3/32" shank - 1/8", 5/32", 3/16", 1/4"), (5/32" shank - 3/16", 7/32", 1/4", 9/32", 5/16"), (3/16" shank - 1/4", 5/16", 3/8", 7/16", 1/2"), (1/4" shank - 5/16", 3/8", 7/16", 1/2", 9/16", 5/8"), (5/16" shank - 3/8", 7/16", 1/2", 9/16", 5/8", 3/4"). Supplied in fitted case or stand.