Latest variator technology from Polini for untuned 50cc engines for improved acceleration and higher top speed. Polini evo sliders make for better power transfer and shifting. No additional tuning required, so a great option for untuned scooters. With untuned scooters, all the parts supplied must be fitted and additional fine-tuning is required. Delivery contains: Hi-Speed variator with sleeve, 1x set of reinforced clutch springs, 1x stronger, calibrated clutch springs, counter pressure spring (22kg) with Evo-sliders and 1x set of variator weights (16x13) at 6.9g. Installation instructions can be found under the plastic inlay inside the packaging.