Actual dimensions are 20 x 23.13 x .75. Accumulair brand 21x23.5x1 American Standard TFE235A1AH30 substitute whole house filters, exactly engineered to replace the original brand American Standard TFE235A1AH30 air filters. Fully assembled so no forming or combs required. MERV rated to ASHRAE 52.2 test classifications assuring particle filtration as good or better than the OEM American Standard TFE235A1AH30 air filter. Photo: The example filter pic as shown is not true to size and is included to show configuration purposes. Trade names and American Standard TFE235A1AH30 identifier included for air filter replacement identification use.