The high performance exhaust fan from AirkingTM features an unique snap-in installation system. 4" round duct collar with a plastic damper to protect against backdrafts and ensure a quiet operation. Can be installed over a shower or a tub if connected on a protected GFCI circuit. UL listed. Including a 26 W GU24 fluorescent bulb (equals a 100 W incandescent bulb). HVI certified. Quick installation. 5-year warranty.