Filter Replacement Set for EWS Four-Stage Reverse Osmosis System With UV (RU400T35-UV) Item No. Included in This Set: PRESED-05, GAC-00, RO-F-INLINE, RO-M-TFC,2 Pin UV-Lamp Description: 5 micron pre-sediment filter, Granular activated carbon prefilter, Granular activated carbon postfilter, TFC membrane Replacement Schedule: Up to 1 year, not to exceed 1 year Filter Codes: 1, 6, 12, & 21 Full-size, full bed depth, USA-made filters for optimum performance and longer life.