Sterling Seal KP-5251083340x6 Purolator Key Pleat Extended Surface Pleated Air Filter, Mechanical MERV 8, 20" W x 25" H x 1" D (Pack of 6) Mechanical MERV8 Filter. Air Flow Capacity listed at 300FPM Low initial resistance for energy savings, Quality Engineered, Consistently Produced, Made of 100% synthetic fibers, Made in the USA for over 30 years Single piece beverage board die cut frame, with structural integrity unlike any self supported filter available today Pleats hold together even when wet! No delaminating, no excessive buckling, no collapsing. Filter can endure impact and deformation and return to its original shape ACTUAL SIZE: 19-1/2" Width X 24-1/2" Height X 3/4" Thick, NOMINAL SIZE: 20" Width X 25" Height X 1" Thick