Keep the explosive low-end acceleration and reach higher top speeds. Dr. Pulley Sliders are counterweights for the scooter's front centrifugal pulley, shaped differently from the usual round rollers, and they can be used in the standard or in an upgraded variator. They slide inside the pulley and regulate the drive more effectively than standard round rollers. They also last longer than traditional cylindrical rollers because they slide. Choose the weight from the gramme options. The manufacturer suggests 10-15% less than standard for better performance. If you are not sure the item you have chosen fits your model, contact us or write your frame number in the comments box that appears during checkout. We check the fitment before we ship your order, we get in touch, and we always send the right part for your model.