This set of nine gram sliding roller weights from Dr. Pulley is specifically designed for use with 50cc to 100cc scooter and motorcycle engines. These roller weights are a great choice for anyone looking to improve the performance of their vehicle without having to worry about the condition of the parts. Made with high-quality materials and designed to fit perfectly with your engine, these roller weights are a reliable and cost-effective upgrade for any scooter or motorcycle enthusiast. 1E