HT Rollers are made using a special formula of CPT and are able to change the gear ratio of your scooter and perfectly control its speed and acceleration. The weight of the rollers becomes the centrifugal force inside the variator and therefore the heavier the rollers the shorter the gear shift time and vice versa; therefore as the weight of the rollers decreases the engine RPM increases and as the weight of the rollers increases the engine RPM decreases. Specifications: Set of 6 x 16x13mm – 4.4g You should research which weight is best for your needs as simply choosing the lightest or heaviest weight is not always the best option. We have many different sets of roller weights that provide different performance results.