HTRolls are made with CPT with a specific formula and their weight is marked on one side. HTRolls represent a technical spare part for the original one, in a complete series of calibrated elements capable of varying your scooter's transmission ratio and perfectly regulating its speed and acceleration. Operation Due to the rotation, the weight of the rollers becomes a centrifugal force; the higher the rollers weight, the lower the gear change time, and vice-versa. Variator calibration To optimize engine's performance, select rollers that in operation, maintain the engine at the highest power regime. By diminishing the rollers weight the engine s RPM increases; on the contrary, by increasing the rollers weight the RPM decreases. Compatible with: - Aprilia: Area 51_S, Rally 50 AC_S, Rally 50 LC_S, Scarabeo 50 Min.AC_S, Sonic 50 AC_S, Sonic 50 LC_S, SR 50 Min.AC 94-_S, SR 50 Min.LC_S - Beta: Ark 50 AC_S, Ark 50 LC_S - Malaguti: Centro 50 AC_S, F10_S, F12 AC_S, F12 LC_S, F15 Firefox_S - Mbk: Booster 50 euro 0-1_S, Booster 50 euro 2_S, Mach G 50 AC_S, Mach G 50 LC_S, Nitro 50_S, Ovetto_S, Stunt 50 euro 0-1_S, Stunt 50 euro 2_S - Yamaha: AEROX 50_S, BW's 50 euro 0-1_S, BW's 50 euro 2_S, neo's 50_S