... O.D.168.30mm)Flush-coupled casing tubes have a box thread at both ends and are connected together ... It also means that the casing tube can have a thinner wall than the coupling, allowing the overall weitht ... .20mmZW: O.D.219.1mmFlush-jointed casing has a heavier wall section than coupled casing and has an ... type of casing used in geotechnical applications. DCDMA Casing tube(BW,NW,HW,PW,SW,UW,ZW) & (NX,HX ...