Merv 8 Pleated Air Filter - 21 1/2" x 23 1/2" x 1" Quantity:12-pack The permanent frame is constructed

The permanent frame is constructed of space-age plastics that are resistant to corrosion

You may know them as washable air or even permanent air filters

if not you can measure it or check the HVAC unit and the owner‰۪s manual

Unlike some permanent custom air filters

This is a 5" MERV 10 HIGH PERFORMANCE AIR FILTER

Merv 8 Pleated Air Filter - 21 1/2" x 23 1/2" x 1" Quantity:12-pack The permanent frame is constructedAny Kind of Filter's Extended Surface Pleated Filters outperform ordinary furnace filters with medium efficiency and are designed for lower pressure drop, and long service life which reduces HVAC equipment maintenance and energy costs. A higher MERV rating means that the air filter that you are about to purchase possesses a higher amount impurity filtration ability than your ordinary filter.