... .BW,NW,HW,PW,SW,UW,ZW 3.NX,HW,PX,SX, 4. 46,56,66,76,86,101,116,131 ... SX: O.D.168.30mm)Flush-coupled casing tubes have a box thread at both ends and are connected together by ... damaged. It also means that the casing tube can have a thinner wall than the coupling, allowing the overall weitht of ... D.176.20mmZW: O.D.219.1mmFlush-jointed casing has a heavier wall section than coupled casing and has an integral ...