THE OS72 UV AIR PURIFIER IS A COMPLETELY SEALED UNIT AND HAS 2 LED LIGHTS WHICH VERIFY THAT THE UNIT AND BULBS ARE OPERATING PROPERLY. IT IS EASY TO INSTALL AND COMES WITH STEP BY STEP DIRECTIONS WITH PICTURES A CUT-OUT TEMPLATE MOUNTING SCREWS AND FOAM TAPE ALREADY ATTACHED. SIMPLY CUT OUT THE TEMPLATE DRILL HOLES INSERT UNIT PLUG IN AND BEGIN ENJOYING FRESH CLEAN AIR.