Aerostar 21 1/2×23 3/8×1 MERV 11 High Efficiency Pleated Air Filter, 6-Pack, …
Each pleated furnace filter has a nominal size of 21.5×23.375×1 and an actual size of 21.5×23.375×0.75. Made in USA. Comparable to MPR 1000 / FPR 7. Actual size 21.5×23.375×0.75. Extends furnace and AC life while lowering energy costs.