The Bicycle Freewheel Cassette is constructed of aluminum alloy materials, High Pressure Steel Plate, anti-rust, non-deformation, wear-resistant, high performance of durability. The Bicycle Chain are made of high quality steel material, durable and practical to use. The ultra-sliding sprocket features tooth profile with contoured shifting gates for clear and smooth shifting even under load. Mountain flywheel, hollow design, super high strength, lead chain slot and mud hole design, light weight, easy to clean. The Chain with safety buckle, quick installation without tool. Compatible With: For , Campagnolo, Sarm and other drivetrain system. Freewheel Cassette Optional model (Speed&Teeth): 9S 11-42T, 10S 11-42T Specification: Bicycle Freewheel Cassette: 9 Speed 11-42T: 11-13-16-20-24-28-32-36-42T; 10 Speed 11-42T: 11-13-15-17-21-24-28-32-36-42T Bicycle Chain Speed: 9 Speed, 10 Speed(Combo Set with Freewheel); Length: 116 Links Package Includes: 1 Set Bicycle Freewheel and Bicycle Chain Note: 1. Please allow 1-2cm measuring deviation due to manual measurement. 2. Due to the different monitor and light effect, the actual color of the item might be slight different from the color shown on the pictures.