SportCrafters’ OverDrive Pro Rollers offer the same power profile as a stationary fluid trainer while delivering the undeniable feel of rollers. With SportCrafters' ARC Power Modulation technology inside the rear drum, you get progressive resistance that accurately mimics a road ride. The durable steel frame stands up to years of hard training, indoors or out. Plus, the folding design allows convenient storage and transport. The rollers feature an adjustable belt for right and left dismounting, and an easily adjusted wheelbase for different types of bikes.