Description
Actual Dimensions: 20.75 x 20.75 x 4.38. Accumulair brand, 21x21x4.5 Ruud PD540018 compatible whole house filters, specifically built to replace original manufacturer Ruud PD540018 filters. Completely built so no forming or combs needed. MERV classified to ASHRAE 52.2 test specifications ensuring particle filtration as good or better than the original brand Ruud PD540018 air filters. Notice: The example filter image as displayed is not true to size and is included to show design purposes only. Company names and Ruud PD540018 P/N are used for air filter replacement purposes.