The Honeywell F111 Series 1 Replacement Washable Pre-Filter was specifically designed to be compatible with all F111A/C Series 1 Models. Save yourself the hassle and expense of purchasing additional filters with Honeywell's solution of washable filters. Once your filter has accumulated a sizable amount of dust, pollen and various other airborne hazards, you now have the option of simply washing your filter instead of discarding it and replacing it with another. These filters were created with longevity in mind and will assist you in saving time, money and any additional effort. Accept no imitations and achieve the ultimate in peace of mind with a Genuine OEM Honeywell product.