China Replaceable Bit 8 1/2" Single Roller Bit with Basis Roller Cones Bit with Cone 1/2/3 Rotary Digging Rock Bit, Find details about China Single Roller Bit, Roller Bit from Replaceable Bit 8 1/2" Single Roller Bit with Basis Roller Cones Bit with Cone 1/2/3 Rotary Digging Rock Bit