Shimano SL-M951 is a high-performance STI lever designed for mountain biking, offering precise and reliable shifting. It features an 8-speed index system for smooth and accurate gear changes, and a release lever for quick and easy shifting. The SL-M951 also has an integrated optical gear display, allowing you to easily see which gear you're in. With its ergonomic design and lightweight construction, the SL-M951 provides a comfortable and efficient riding experience.