The PUR Plus RF-9999 Faucet Filter Replacements are a set of 5 sealed bags of water filter cartridges designed for the PUR Advanced and Basic models (FM-3700, FM-4100, FM-9400 and FM-2000). Made from stainless steel and featuring a carbon/charcoal filtration method with 3 stages, these blue filters provide clean and refreshing water for your kitchen. With a manufacturer warranty of 1 month, these filter replacements ensure your faucet continues to dispense safe and tasty water for an extended period of time. —opened box—