146mm Double Head Casing Drilling Bit System Zhuzhou Rockking Engineering Machinery Co., Ltd. Base Info Model NO.：146mmSurface Treatment：Spray-PaintManufacturing Process：ForgingMaterial：Alloy SteelTrademark：ZZROCKKINGTransport Package：Wooden BoxesOrigin：China Description Pre：133 Double Head Casing Drilling Bit System Next：168mm Double Head Casing Drilling Bit System
