Lennox X8796 Maintenance Kit for PCO16-28 PureAir Air Cleaner.  This maintenance kit includes: (1) MERV 16 pleated filter model X8789 (1) PCO metal insert model X8792 (2) UV Lamps Model X8794* Replace metal insert and lamps every 24 months. Replace insert more frequently if you notice a significant drop in odor removal efficiency. If you find that you need to replace the  insert more frequently than every 24 months, consider source reduction and/or ventilation to reduce the levels of contaminants in your home Note: DO NOT WASH metal insert. Washing will destroy the titanium dioxide catalyst that coats the insert surface. *Bulb shape may appear different depending on supply.