Description
Actual dimensions are 20.75 x 20.75 x 4.38. Accumulair brand: 21x21x4.5 Rheem PD540018 style whole house air filters, exactly designed to be an alternative to the original brand Rheem PD540018 air filters. Completely box-formed with no forming or combs required. MERV rated to ASHRAE 52.2 test specs establishing function to the level of the name brand Rheem PD540018 filters. Photo: Sample air filter image as displayed is not true to size and is shown for construction purposes. Trade names and Rheem PD540018 P/N included for air filter style identification purposes only.