... are manufacturer 2.BW,NW,HW,PW,SW,UW,ZW 3.NX,HW,PX,SX, 4. 46,56 ... ,116,131,146 WCasing Tube (X and W Series)We are leading manufacturer of Impregnated/ surface-set ... core lifter, core lifter case, Core Barrels, etc.X series casing (Casing Type: NX : O.D.88.9mm ... This can be important when drilling to greater depths.W series casing (Casing Type: BW : O.D.73.0mm ... tube(BW,NW,HW,PW,SW,UW,ZW) & (NX,HX,PX,SX)