The UV Bulb Tray for Vornado Silverscreen Enhanced Air Purifiers emits UV light to activate the titanium dioxide coating on screen to break down harmful viruses, bacteria and gases that HEPA and Carbon cannot capture. Recommended replacement is every year with continuous use. Contains 1 UV bulb tray. Vornado’s Automatic Filter Refill Program for Vornado Air Purifiers offer a convenient way to receive regular shipments of Vornado filters for your Vornado Air Purifier! Eliminate the hassle of remembering to reorder. Maintain the high efficiency of your Vornado Air Purifier by never running out of new filters. Receive FREE SHIPPING on all air cleaner filter refill orders when you set up a product subscription. Click the “Subscription Wizard” button above to set a customized schedule to receive your filters – conveniently billed automatically. This UV Bulb Tray, part number MD1-0026, works with models PCO200, PCO300, and PCO500 Silverscreen Enhanced Air Purifiers.