Actual size is 20 x 23.13 x .75. Accumulair brand, 21x23.5x1 American Standard TFE235A1AH20 compatible whole house air filters, specifically built to replace name brand American Standard TFE235A1AH20 air filters. Fully box-formed so no assembly or combs required. MERV classified to ASHRAE 52.2 test specs establishing performance equal to the original manufacturer American Standard TFE235A1AH20 filters. Photo: Example filter image as shown is not to scale and is included to show design purposes. Name brands and American Standard TFE235A1AH20 P/N are used for air filter replacement identification only.