CycleOps made its Rollers with precision-lathed aluminum roller drums that won't distort, an adjustable belt for right and left dismounts, and a foldable design for easy storage. Rollers force you to concentrate on balance, control, and riding in a straight line, all of which help improve your efficiency and technique on the road. The Rollers' durable steel-frame construction won't bend or kink. If you're stoked on having additional resistance while you train, choose the Aluminum Rollers With Resistance. A magnetic bar works with the rolling aluminum rear drum to increase your resistance with five different levels.