Description
Actual size is 20.75 x 20.75 x 4.38. Brand: Accumulair. 21x21x4.5 Ruud Protech 540018 style whole house filters, exactly constructed to be an alternative to the original brand Ruud Protech 540018 air filters. Fully box-formed so no assembly or combs needed. MERV rated to ASHRAE specifications assuring performance as good or better than the original brand Ruud Protech 540018 filters. Note: The example filter image displayed is not true to size and is displayed for configuration purposes. Brand names and Ruud Protech 540018 part numbers are listed for filter replacement purposes.