HealthSmart 19 x 21 AC filter / Furnace filter with (1) BioSponge Plus Replacement Provides maximum protection against airborne contamination. Actual size: 19 x 21 x 3/4" Saves you time and money, clean systems use less electricity, and breakdown less often Includes: (1) permanent aluminum frame & (1) BioSponge Plus refill. Simple to use, easily fits all makes and models of furnaces and air conditioners--any size available 10 Year Warranty, you'll always have a filter that fits and performs perfectly.