Casing Tube 1.We are manufacturer 2.BW,NW,HW,PW,SW,UW,ZW 3.NX,HW,PX,SX, 4. 46,56, ... when drilling to greater depths.W series casing (Casing Type: BW : O.D.73.0mm NW: O.D.88.90mmHW: O ... type of casing used in geotechnical applications. DCDMA Casing tube(BW,NW,HW,PW,SW,UW,ZW) & (NX,HX,PX,SX)