GUARDED EXHAUST FANS FEATURE 120V SINGLE-PHASE TOTALLY PERMANENTLY LUBRICATED MOTORS WITH PROVISIONS FOR DIRECT WIRING UL CUL LISTED AND CONFORMS TO UL507 STANDARD. THESE SHUTTER MOUNTED FANS INSTALL ON INSIDE WALL AND ELIMINATE THE NEED FOR EXTERNAL FRAMING AND SHUTTER. QUIET OPERATION MAKES IT IDEAL FOR COMMERCIAL ENVIRONMENTS. ALUMINUM BLADES ARE ENCLOSED IN A STURDY STEEL SPIRAL WIRE GUARD. NOTE ROUGH-IN HOLE SIZE IS 1/2"" (+/- 5/16) LARGER THAN FAN BLADE SIZE. THE PRODUCT HAS A LIMITED WARRANTY OF 1 YEAR.