Shimano FD-TY21 is a front derailleur designed for smooth and precise gear shifting on bicycles. It features compatibility with SIS (Shimano Index System), ensuring accurate shifting performance. The derailleur is suitable for triple chainwheels and offers a wide range of adjustment options to accommodate different frame geometries and chainring sizes. It also includes a cable tension adjuster for fine-tuning shifting precision. With its durable construction and reliable operation, the Shimano FD-TY21 is an excellent choice for cyclists seeking reliable front shifting performance.