Kreitler Alloy Rollers with Killer Headwind Fan Drums and Alloy End Caps, 4.5-Inch 100-Percent Made in the USA Available in various drum diameters (4.5-Inch, 3.0-Inch, 2.25-Inch) and all are 15-Inch wide The Killer Headwind fan is a great add-on that features adjustable resistance and a cooling breeze; The fan unit can be rotated to point the airflow low or high Includes belt and Standard Frame which covers a wide range of wheelbases