146mm Double Head Casing Drilling Bit Nanjing Xiangyu Paper Products Co., Ltd. Base Info Model NO.:146Surface Treatment:Spray-PaintManufacturing Process:ForgingMaterial:Alloy SteelTrademark:ZZROCKKINGTransport Package:Wooden BoxesOrigin:China Description Pre:R28, R32, R35, R38, T38, T45, Thread Button Drill Bit Next:168mm Double Head Casing Drilling Bit