11-3/4 x 11-3/4 x 3/4 actual size (12 x 12 x 1 nominal size). Our 12x12x1 air filter is an extended surface pleated filter, which outpaces standard air filters with medium efficiency, and are engineered for lower pressure drop, and extended service life, which reduces HVAC equipment maintenance and energy costs. This 12x12x1 air filter is classified to ASHRAE test standards 52.2, which assures that the air filter will capture debris as good or better than original manufacturer 12x12x1 air filters. Pleated design. MERV graded to ASHRAE grades. 295 cfm flow rate.