133 Double Head Casing Drilling Bit System Zhuzhou Rockking Engineering Machinery Co., Ltd. Base Info Model NO.:133mmSurface Treatment:Spray-PaintManufacturing Process:ForgingMaterial:Alloy SteelTrademark:ZZROCKKINGTransport Package:Wooden BoxesOrigin:China Description Pre:118 Double Head Casing Drilling Bit System Next:146mm Double Head Casing Drilling Bit System