... increases gauge holding capability.3. Bearing StructureAir cooling roller bearing package. Balls lock the cone which ... mining applications.5. 5.Current Main AvailabilityDiameter/InchIADC CODE3 1/2 211, 121, 241, 537….3 7/8 ... 1/2 211, 121, 241, 537….14 3/4 131, 211, 537, 517….15 1/2 211, 121, 241, 537….17 1/2 ... 131, 211, 537, 517….18 1/2 211, 121, 241, ...