Tier1 Replacement for GeneralAire 20x25x5 Merv 11 14201 & 4501 AC Furnace Air Filter 2 Pack MERV 11 rating captures 90% of particles, 1-3 microns in size Replacement for: GeneralAire 14201, 5FM2025, 4501, Trion / Air Bear 255649-102, 259112-102, 259112-105, 229990-102 and 248713-102 General has started rounding the dimensions on their 5-inch filters. These filters still fit the same, they just no longer contain fractions in the description Replace the filter every 6 months