Qualtech Counterbore, Round Shank, Series: DEWCBR, 27/64 in Bore dia, 4-1/16 in Overall Length, 3/8 in Shank dia, 5/32 in Pilot Shank dia Compatibility, HSS, Bright Qualtech DEWCBR27/64 Round Shank Counterbore, 27/64 in dia Bore, 3/8 in dia Shank, 4-1/16 in OAL, HSS, Pilot Shank dia Compatibility: 5/32 in