Product 221/745
The Honeywell FC40R1052 Return Grille Filter is a high-efficiency, long-life replacement for return grille applications. It captures a significant amount of the airborn particles in the air that circulate through the filter. The FC40 series has a MERV 10 rating.
Honeywell recommends allowing a depth of four to seven inches behind the grille to provide space for the deeper filter and airflow through the filter.