216mm Double Head Casing Drilling Bit 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 Next：Double Head Casing Drilling Bit System for Mining/Waterwell
