Fitting 3/8" x 5/16" Reducing Union JG-PI201210S
5/16" O.D. is used for Culligan and Ecowater ( Sears Kenmore ) brine tubing.
3/8" O.D. is the more common size brine tubing used by all other residential valve models ( Fleck, Autotrol, Clack, Rainsoft, etc ).
This fitting could be used to "adapt" from one size Brine Tubing to another when using standard 3/8" brine tank with Culligan.
Or using existing Culligan or Ecowater ( Sears type ) brine tubing / brine pick up assembly with a "standard" valve using 3/8" O.D. brine tubing connection.Information on Removing and Connecting the Tubing using Quick Connections,
see: How to Use Quick Connect Fittings - Video