This Water Filter Cartridge Refill pack includes two replacement filters for your Keurig® Water Filter Starter Kit accessory (sold separately). Simply place a cartridge into the Water Filter Assembly and insert into your water reservoir. For best results, replace your water filter cartridge every 2 months or 60 tank refills. For use exclusively with the following Keurig K-Cup® and Vue™ Brewers purchased after August 2007: Elite B40, Classic B44, Ultra B50, Signature B60, Special Edition B60, Ultimate B66, Platinum B70, Select B77, Platinum Plus B79, B150, OfficePRO® Premier B155, V600 and V700. It is not compatible with the Rivo™ System.