Complete 12-Month Filter Set: The F4DS-MAX set lasts up to 12 months and includes 1×FCPFDS, 1×FCNCDS, 1×FCPBDS, and 1×FTDS, offering a full replacement solution for iSpring DS4B-MAX and DS4S-MAX bottleless water dispensers SGS-Tested Premium Filtration: Designed for discerning users who demand superior water quality, the first three stages feature SGS-tested carbon block filters that remove up to 99% of PFAS, chloramine, and lead, while the fourth stage FTDS post-carbon filter enhances taste for both safety and exceptional flavor Freshness Preserved in Every Filter: Each cartridge is individually sealed to maintain freshness until installation, and users should unwrap all cartridges before installation and flush the system for 3 to 5 minutes prior to drinking Hassle-Free, Tool-Free Installation: The F4DS-MAX filters are designed for quick, easy replacement with iSpring DS4B-MAX and DS4S-MAX models, making routine maintenance simple and fast Not for TDS Reduction: This filter set does not reduce Total Dissolved Solids (TDS) like a reverse osmosis membrane, so customers seeking TDS removal should consider an iSpring Reverse Osmosis (RO) system