This is a compatible replacement filter for the Honeywell FC40R1037 return grill filter. It has a MERV 10 efficiency rating allowing it to capture unwanted indoor air contaminants like pet dander, dust and pollen. This filter lasts approximately 6 months depending on use.
Nominal size: 12x24x4-3/8
Actual size (with header): 11-3/4 x 23-3/4 x 4-3/8
Also known as FC40R-1037.