The Culligan S1A 2-pack Medium Filtration cartridge reduces sediment, rust, scale, dirt, coarse sand, sand and silt. The replacement cartridge is designed for use in the following Culligan model filter housings: HF-150A, HF-160, HF-360A, WH-S200-C and most other brands standard size housings. The filter is not recommended for use with non-treated well water supplies. The cartridge life is up to 4 months or 16,000 gallons.