Abstract: A connection between the outlet of a flush valve and a flush tube includes an outlet fitting for the flush valve having an exterior thread thereon and a flush tube which extends within the outlet fitting. A coupling nut having an interior threaded area for attachment to the fitting also has an inwardly-directed annular shoulder which extends closely adjacent the flush tube and with the end of the fitting, defines an annular chamber. Positioned within the annular chamber is an annular elastomeric gasket in contact with an end of the fitting and in peripheral contact with the flush tube. A back-up ring is positioned within the chamber for circumferential contact with the gasket and a clip ring is positioned within the chamber between the back-up ring and the coupling nut shoulder and is adapted for surface penetration engagement with the exterior of the flush tube.