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