23.5X29.5X.75 actual size (24 x 30 x 1 nominal size). This 24x30x1 air filter is an extended surface pleated filter, which outpaces standard air filters with medium efficiency, and are engineered for lower pressure drop, and increased service life, which reduces HVAC equipment maintenance and energy expenses. This 24x30x1 air filter is measured to ASHRAE test standards 52.2, which establishes that the air filter will capture debris as good or better than original brand 24x30x1 air filters. Pleated design. MERV rated to ASHRAE ratings. 1475 cfm flow rate.