These high quality accessory 20×15 roller weights for scooters are from NCY, a very well known manufacturer of aftermarket competitive riding scooter parts and accessories These high quality roller weights are constructed with a low-friction polymer to ensure a long life and superlative operation Description These high quality accessory 20×15 roller weights for scooters are from NCY, a very well known manufacturer of aftermarket competitive riding scooter parts and accessories. These high quality roller weights are constructed with a low-friction polymer to ensure a long life and superlative operation. The 20 x 15mm weights is the OEM size on the Honda PCX and the Genuine Blur 220i. The Genuine Blur 220i takes 14.5g stock rollers. 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 acceleration. If you??re a heavy person (and/or) if you have a stock motor you will want to lean towards the lighter rollers. If you are a light person (under 140 lb.) or you have a big bore you will want heavier rollers. Let Monster Scooter Parts be your source for NCY scooter parts and accessories. WARNING California Residents : Proposition 65 Warning