HHIP 2007-0021 21 Piece HSS Interchangeable Pilot Counterbore Set 21 PIECE HSS INTERCHANGEABLE PILOT COUNTER Bore SET; 14 Pilots: 5/32" Shank : 0.187, 0.204, 0.213, 0.229, 1/4, 17/64, 9/32, 5/16, 21/64, 11/32, 3/8, 25/64, 13/32 & 7/16"; 6 Counterbores: 5/16, 3/8, 7/16, 1/2, 9/16, 5/8", Straight Shank 1 Holder: 3/8" Shank , Supplied in fitted case Straight Shank; High speed steel 1 Holder: 3/8" Shank , Supplied in fitted case