216mm Double Head Casing Drilling Bit System Zhuzhou Rockking Engineering Machinery 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 System Next：R32 T45 T51 Threaded Tungsten Carbide Button Drill Bits
