Handy resource for purchasing replacement filters. For use with various Fountain Industries / Kleen Tec parts washers. For use with solvent based parts washers. Keeps your detergent cleaner for a longer period of time, thus extending the life of your detergent. Detergent is expensive. If you can triple to life expectancy of it, you will save thousands of dollars over the life of your parts cleaner machine. Don't be penny wise and pound foolish. Get a washer that has filtration. It's an investment that will pay for itself in a very short period of time. Sold in a six pack. Stock up and save.