Innovative Wind Ring air system provides high volume air movement. Save-Smart – Less than 2 cents per hour. Three quiet speeds Durable Steel Body. Two-year limited warranty ETL Listed. Step up to the Premium Box Fan and enjoy the benefits of the Wind Ring System, an exclusive grill design that focuses the air movement, increasing its velocity. Three, Whisper-Quiet Speeds. 30% More Air Velocity than Most Standard Box Fans. Energy-Efficient, High Volume Air Movement. Wide-Body Design for Stability. U.L. Listed.