Sterling Seal FI-0504-SP1 Purolator Hi-E 40 Extended Surface Pleated Air Filter, Mechanical MERV 8, 20" Width x 25" Height x 4" Depth (Pack of 6) Mechanical MERV8 Filter Exceeds ASHRAE Standard 62 air cleaning specifications for filters installed upstream of cooling coils Low initial resistance for energy savings, Quality Engineered, Consistently Produced, Made of 100% synthetic Fibers, Made in the USA for over 30 years Two-Piece Frame Construction - will not rack, warp, or bend under normal handling or operating condition ACTUAL SIZE: 19-1/2" Width X 24-1/2" Height X 3-3/4" Thick, Nominal Size 20" Width X 25" Height X 4" Thick