Function of product: Our High performance spring can increase speed and reduce clutch failure, 1500RPM Springs will give you the greatest grabbing power and a higher RPM at take-off.Sacrifice some speed to give you more power when you go uphill. Fits: 50cc-100cc GY6, also fits 139QMB and 1P39QMB Engines Scooter Moped ATV You will get: 1*High Performance 1500RPM Racing Torque, 3*Clutch Shoe Springs Production materials: High strength materials, provide stable performance, give you longer use. The surface coating is firm and not easy to fall off. It has a glossy appearance and decorates your motorcycle Please Note: Please check carefully whether the product matches your motorcycle. Please be clear about the spring performance you want. The performance of 1000-2000 rpm is different. The exact performance of upgrade parts will be affected by many other factors. Product Description AH is specialized in providing parts and accessories for Off-Road Motorcycles, Karting, ATV and Scooters/E-Sco