168mm Double Head Casing Drilling Bit System Nanjing Xiangyu Paper Products Co., Ltd. Base Info Model NO.:168mmSurface Treatment:Spray-PaintManufacturing Process:ForgingMaterial:Alloy SteelTrademark:ZZROCKKINGTransport Package:Wooden BoxesOrigin:China Description Pre:146mm Double Head Casing Drilling Bit System Next:216mm Double Head Casing Drilling Bit System