Honeywell FC100A1011 20 x 20 x 4 inch replacement media air furnace filter
Replace them every 6-12 months versus monthly or quarterly changes.
Genuine Honeywell FC100A1011 20x20x4 Inch Replacement Air Furnace Filter 2 PACK
They are rated to indpendent ANSI Honeywell FC100A1037 Filter F25F F35F F100F F200E 5pk features.