Valve Body ( with NO internal parts ) for Downflow Fleck 5000, Proflo SE, and others water softener valves.
Also used in newer Rainsoft Valves ( as it is based on the Fleck 5000 Valve Body design ).
Includes top of tank o-ring ( 18303 ) and Slip Ring ( 18569 ) is included with the valve body.
Cross reference = 17863 (Composite Valve Body)
You might also consider a complete new valve head replacement,
Replacing Rainsoft Valve.