Toilet flush-valve tailpiece and stop repair parts are components for replacing the fittings that connect a flush valve (flushometer) to the water supply and control flow through the valve. Tailpieces are couplings and sleeves that fit between the flush valve and the water pipe. Stops have a screw that can be turned to adjust water pressure for proper flushing and to stop or start flow during maintenance. Tailpieces and stops may need replacing when they leak or no longer allow flow and pressure to be controlled or adjusted.