Variator rollers for 125–150 cc 4-stroke scooters. Under centrifugal force they move outward and change the position of the belt on the pulleys, and the acceleration performance depends on them.
The rollers are replaced when worn: flat spots appear on them, acceleration gets worse, and jerking and noise occur. The 15 g in the name is the weight of a roller (15 grams). It is better to replace the whole set so that the rollers are of the same weight. Equal roller weight is important for smooth operation: a worn roller causes vibration and uneven acceleration.
