Bike Cassette Freewheel, 11-Speed Cassette Freewheel Sprocket 11-50T Road Bike MTB Mountain Bike Cassette Freewheel Replacement ★ Adopt a hollow design. While reducing weight, it can also increase speed. ★ The bicycle flywheel is resistant to high temperature, corrosion, rust, non‑deformation. ★ High wear resistance, durability, impact resistance, strong compatibility, so that more possibilities for riding. ★ Easy to install, no adjustment is required, stable gears and accurate positioning are provided within the range. ★ Wide tooth ratio mountain flywheel with large tooth ratio for single tooth disc. It's easier to climb a hill. Specification: Item Type: Bike Freewheel Material: Chromium-molybdenum steel Color: As Pictures Shown Weight: Approx. 644g/22.7oz Specifications: 11 speed 11-50T Small teeth: 11 T Teeth: 11-13-15-18-21-24-28-32-36-42-50T Black Big Teeth: 50T Wide tooth ratio mountain flywheel, large tooth ratio flywheel, for single tooth disc. It's easier to climb a hill Package List: 1 x Bike Freewheel