Complete expansion tank system for your “Single Tank” Gen 1 through Gen 4 systems. Includes base and all required plumbing. (U.S. Patent Number 10,851,005 + CIP)Easily attaches to the KC Car Wash primary system(s) Gen1 – Gen 4 in minutes adding an additional 45 gallons of daily wash water capacity. Enough total volume to wash six to over ten cars per day or larger stuff like your House/RV/Toy Haulers and a few cars or toys to boot if you wish. Caution: Expansion tank must sit level to or slightly higher than the primary tank to avoid overfilling.