China Single Roller Cutter 12 1/4" IADC Code 637 with Straight Shank Single Roller Bit Cone 1/2/3 Replaceable Drill Bit, Find details about China Single Roller Bit, Roller Bit from Single Roller Cutter 12 1/4" IADC Code 637 with Straight Shank Single Roller Bit Cone 1/2/3 Replaceable Drill Bit