This product is a 4-pack of PUR PLUS Replacement Mineral Corr Filter RF-9999, designed for use with Aqua Optima and Brita water filter systems. The filters are made of blue plastic and are suitable for commercial and household use. They have a carbon/charcoal filtration method and can remove lead contaminants. With a capacity of 100 gallons each, these filters are compatible with models such as Samsung Aquarius, Aqua Optima Evolve, and Brita Maxtra+. This brand new product ensures clean and safe drinking water for you and your family.