20 In. Wind Ring box fan provides powerful air delivery. Larger body size allows more air into the 5 plastic paddle blades. Wind Ring in grill focuses air into blades. 3-speed quiet operation, energy efficient. Durable steel body with plastic safety grills. Convenient carry handle, easy assembly. 21-3/8 In. W. x 22-1/2 In. L. x 5-3/8 In. D. UL (Underwriter's Laboratories) listed. ETL approved.