9.5x24.5x.75 actual size (10 x 25 x 1 nominal size). This 10x25x1 air filter is an extended surface pleated filter, which exceeds ordinary air filters with medium efficiency, and are designed for decreased pressure drop, and long service life, which reduces HVAC equipment maintenance and energy expenses. The 10x25x1 air filter is governed to ASHRAE test standards 52.2, which establishes that the air filter will operate as good or better than original brand 10x25x1 air filters. Pleated design. MERV rated to ASHRAE grades. 512 cfm flow rate.