These high quality accessory 20×12 roller weights for scooters are from NCY, a very well known manufacturer of aftermarket competitive riding scooter parts and accessories Roller weights are used for fine tuning your scooter to get the most out of what you need from your machineDescription These high quality accessory 20×12 roller weights for scooters are from NCY, a very well known manufacturer of aftermarket competitive riding scooter parts and accessories.Roller weights are used for fine tuning your scooter to get the most out of what you need from your machine. A good set of roller weights are an important tuning device and they will have a significant impact on your scooter’s performance, however flat spots can develop from long use and negatively affect performance.Tuning Tips: Light rollers are good for quick acceleration, stop and go riding and hills, but you loose top end speed. Heavy rollers will give you a higher top end speed (long roads) but you will loose low end acc