Accumulair 21x27x5 (20.7x26.2x5) Carbon Odor Block Aftermarket American Standard Replacement Filter Nominal Size: 21x27x5 Actual Size: 20.7x26.2x5 Carbon impregnated disposable pleated panel filters. A simple solution for controlling both odors and dust particles! Lasts up to 6 months. This filter is made by Accumulair.