Traps 95% of airborne dust and allergens Permanent & Washable - Just hose off and reinstall Replaces disposable furnace filters Made in USA Self-charging electrostatic filter media - does not require electricity This filter measures EXACTLY 18-1/2 X 24-1/2 X 7/8 inches. Tired of having to remember to buy that furnace filter every 3 months? Tired of your house being dusty? Replace your disposable air filter with a washable electrostatic filter. It traps more dust and allergens, has a durable metal frame and comes with a great warranty. Just hose off, allow to dry for 15 minutes and reinstall.