This is a compatible replacement filter for the Honeywell FC40R1011 20x25 return grille filter. Like the Honeywell FC40R1011, this filter has a MERV 10 efficiency allowing it to capture small indoor air pollutants.
Nominal size: 20x25x4-3/8
Actual size (without header): 18-1/4 x 23-1/4 x 4-3/8
Actual size (with header): 19-3/4 x 24-3/4 x 4-3/8
Also known as FC40R-1011.