SHIMANO Altus RD M310 Rear Derailleurs for MTB bikes. • Compatible with 3x7S, 3x8S, 21S, and 24S speed bikes. • Made of durable metal material. • Perfect for outdoor cycling and mountain biking. • High-quality bike accessory from SHIMANO. • Enhances bike performance and gear shifting. • Not foldable. • Suitable for other bike parts.