Made from high-quality aluminum 7075-t6. This high-grade aluminum has a tensile strength of 74,000 PSI and a yield strength of 63,000 PSI. Simply stated, it is a strong alloy and will take abuse for years of use. The 54 and 60 tooth option is the cheapest way to gain low-end power for your E-bike especially if you have bigger or heavier tires. We have found this extremely helpful if you riding on sandy terrain, or need more power getting out of tight corners. Fitment All Sur Ron LBX Models All Segway X260 Models