... ,66,76,86,101,116,131,146 WCasing Tube (X and W Series)We are leading manufacturer of Impregnated/ surface-set diamond ... Wall Bit, core lifter, core lifter case, Core Barrels, etc.X series casing (Casing Type: NX : O.D.88.9mm HX: O ... . This can be important when drilling to greater depths.W series casing (Casing Type: BW : O.D.73.0mm NW: O ...