HO Diaphragm for 6 Concor Superliner Cars. Gray only. Includes adapter for close coupling, Kadee® style coupler installation and more precise truck mounts. Close the gap with our innovative injection molded operating diaphragms. This easy to assemble kit turns a string of passenger cars into a train. Diaphragms stay connected in turn radii over 24 inches and have no minimum radius for smooth operation. Instructions are included with all kits.