Traditionally, the gear ratio in scooter CVTs is changed by the in-and-out rolling movement of the roller weights With the innovative Dr Pulley sliding roller weights, the roller weights slide inward and outward in the Movable Drive Pulley (MDF) to change/extend the gear ratioDescription Traditionally, the gear ratio in scooter CVTs is changed by the in-and-out rolling movement of the roller weights. With the innovative Dr Pulley sliding roller weights, the roller weights slide inward and outward in the Movable Drive Pulley (MDF) to change/extend the gear ratio.These roller weights fit many 50cc scooters including the Honda Ruckus, Honda Elite LX SR (SA50), Honda Metropolitan (CHF50), and the Yamaha Zuma. WARNING California Residents: Proposition 65 Warning Specifications Size: 16x13Available Weights: 5.0g, 5.5g, 6.0g, 6.5g, 7.0g, 7.5g, 8.0g, 8.5g, 9.0g, 9.5g