The ELECTRA GOLD 9400 Washable A/C Furnace Air Filter - Permanent, Reusable, Electrostatic - Never Buy Another Filter - Aluminum Frame - Made in US Traps 95% of airborne dust and allergens Permanent & Washable - Just hose off and reinstall Replaces disposable furnace or A/C filters Made in USA - Lifetime warranty Self-charging electrostatic filter media - does not require electricity