Universal Security Instruments Bathroom Exhaust Fan with Custom-Designed Motor, 50 CFM, Model BF-504 Bathroom exhaust fan combines high function with practical design to keep air moving and effectively pull out moisture Comes equipped with a 50-CFM 3.5-sones motor that is permanently lubricated so that it will not get louder over time Covers up to 60 square feet of living space and includes 4-inch duct adaptor with built-in damper Keyhole slots on the blower bracket simplifies installation so you can have a fully-functioning bath fan in no time Comes with a three-year limited warranty