Expect better performance from your scooter, period. No matter what stage you are in upgrading your scooter, simply add Dr. Pulley weights and a kevlar belt for a power upgrade. Dr. Pulley roller weights are the most advanced weights available. These sliding rollers perform better than standard round weights by allowing the variator to open farther for higher top speeds, and last longer with less performance material loss. The weights have several unique features such as their composite material containing nylon for better performance.