Lennox X6673 20x25x5 Reusable Filter Frame Kit - Includes Lifetime Reusable Frame MODEL # RFFS 873 and 6 Replacement Filters PART # PP-873 MERV 11. Made by FurnaceFilters.CaReplaces Lennox Healthy Climate Part # X6673, Model HCF20 11 20x25x5 Actual Size : 19 3 4" x 24 3 4" x 4 3 8" Replacement Pleat Packs PART # PP 873 MERV 11 is for use with Model # RFFS 873 Reusable Filter Frame System is Listed Below. Kit Includes Lifetime Reusable Frame MODEL # RFFS 873 and 6 Replacement Filters PART # PP 873 MERV 11. One Replacement Filter lasts Up to 6 Months. Reusable Frame System saves up to 90% of Storage Space and up to 90%