China 12 1/4" Single Roller Bit with Basis Replaceable TCI Bit Rock Drilling Tools Roller Cone S Bit with Cone 1/2/3 IADC Code 637, Find details about China Single Roller Bit, Roller Bit from 12 1/4" Single Roller Bit with Basis Replaceable TCI Bit Rock Drilling Tools Roller Cone S Bit with Cone 1/2/3 IADC Code 637