This is a pack of 3 water filter cartridges compatible with Brita Maxtra and Maxtra+ style water filter jugs. These cartridges are designed to reduce limescale, chlorine, and other impurities, improving the taste and odor of your water. Each cartridge lasts approximately one month. Please note that these are compatible parts and not genuine Brita products. They are designed to drop into the top of the filter jug; they will not fit jugs that use a twist and lock mechanism. This new version fits all Brita Maxtra style filter jugs, replacing the standard Brita Maxtra, Maxtra+, and Maxtra PerfectFit.