10x20x1 Electrostatic Washable Permanent A/C Furnace Air Filter Electro-static polypropylene mesh Polyester media Extruded galvanized frame Galvanized wire mesh screening Made in USA Traps 95% of airborne dust and allergens Permanent & Washable - Just hose off and reinstall Replaces disposable furnace filters Lifetime warranty Self-charging electrostatic filter media - does not require electricity