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