Actual Size: 20 x 23.13 x .75. Accumulair brand 21x23.5x1 American Standard BAYFTAH23W1A compatible whole house air filters, specifically constructed to replace original brand American Standard BAYFTAH23W1A air filters. Completely box-formed with no forming or combs required. MERV classified to ASHRAE specifications establishing particulate filtration as good or better than the original brand American Standard BAYFTAH23W1A air filter. Note: Example air filter picture shown is not the actual dimensions and is there to show configuration only. Name brands and American Standard BAYFTAH23W1A P/N included for air filter substitution purposes only.