Hart & Cooley 659 Series 20" x 10" White Return Air Filter Grille #043415 (Fits a 20"W x 10"H Hole) Designed to fit a 20"W x 10"H hole; actual size is 22-5/8"W x 12-5/8"H x 1-5/8"D. All-steel construction; bright white finish. 1/3" spaced fins set at 20 degrees. Use standard 1" thick disposable filters (not included). Removable face for easy installation and cleaning.