Description
Actual dimensions are 20.75 x 20.75 x 4.38. Accumulair brand, 21x21x4.5 Ruud Protech 540012 style whole house filters, specifically constructed to replace the original manufacturer Ruud Protech 540012 filters. Fully assembled - no forming or combs needed. MERV rated to ASHRAE classifications ensuring particle capture equal to the original manufacturer Ruud Protech 540012 filter. Photo: Sample air filter picture shown is not to scale and is included to show design purposes only. OEM names and Ruud Protech 540012 identifier are listed for filter substitution purposes.