Great for the mountain bike lovers. Features: Iron material， durable and useful. You can ride freely with the product. Suitable for most of mountain bikes. Specifications: Material: Iron Color: Silver Cog: 13 Item Weight: 311g / 10.99oz Package Size: 25 * 20 * 5cm / 9.84 * 7.87 * 1.97in Package Weight: 321g / 11.31oz Package List: 1 * 7 Speed Rear Derailleur