PUR's RF-9999 Faucet Water Filters feature PUR's most advanced 3-stage filtration system. The first stage removes sediments and the second stage filters out metals and other pollutants. The third stage works to greatly improve the taste and smell of the water. The filters are designed to be easily changed and can last up to 3 months or 100 gallons, depending on the amount of usage. The convenient 3-pack of RF-9999 filters will last approximately nine months.  The simplest product for your filtration needs is the Pur water filter pitcher.