Model: ST-EF51 - Performance: Experience seamless shifting with 21 speeds (3 x 7 configuration) for optimal gear selection tailored to your riding needs, ensuring efficiency on various terrains. - Compatibility: Designed to fit a wide range of bicycles, making it an ideal upgrade for both casual riders and serious cyclists looking to enhance their performance. - Durability: Crafted from high-quality materials, the ST-EF51 is built to withstand the rigors of cycling, ensuring long-lasting performance and reliability on every ride. - Weight: Weighing just 353 g, this product offers a lightweight solution without compromising on strength, making it perfect for competitive riders who prioritize speed and agility. Use Scenarios: 1. Commuting: Tackle daily commutes with ease, allowing you to switch gears effortlessly as you navigate through city streets and varied elevations. 2. Recreational Riding: Enjoy leisurely rides in the park or on trails, knowing you have the flexibility to shift gears according to the terrain, enhancing your overall cycling experience. 3. Competitive Cycling: Elevate your game during races with precise gear changes that enable you to maintain speed and control, giving you an edge over the competition. The ST-EF51 is not just a gear shifter; it's a reliable companion for cyclists seeking enhanced performance and versatility.