24" Direct Drive Whole House Fan With Automatic Shutter, Pulls Air From A House Size Of 1500 SQFT, 4500 CFM, 110v,Runs On High & Low, 2 Speed Pull Chain Included, Needs 864 SQIN Of Open Exhaust Vents In Attic Space, Rough Opening Is 27-3/4" x 29", Automatic Shutter Is White, Do Not Have To Cut Joist When Installing Fan For Easier Installation, 10 Year Limited Parts Warranty, 5 Year Limited Labor Warranty.