Features1Aluminum Alloy Material: 9 speed cassette is made of aluminum alloy, which is suitable for various harsh riding environments. Anticorrosion, good heat resistance, and long service life. 2Smooth Rotation and Noiseless: Bicycle freewheel provides smooth rotation and operates quietly, enhancing the overall riding experience. 3Accurate Internal Thread: The high accuracy internal thread ensures a tight connection with the bicycle hub, improving stability and power transfer. 4Hollow Design: The hollow design helps to reduce weight and alleviate the burden during cycling. It achieves a good balance between strength and weight, making it easy to install and use. An ideal choice for reducing the weight of your bicycle. 5Easy Installation: Bike cassette is designed for convenient installation, making it easy for users to replace or upgrade their existing bike freewheel.SpecificationItem Type: 9 Speed CassetteMaterial: Aluminum AlloyWeight: Approx. 560g / 19.8ozPackage List1 x 9 Speed Cassette3 x Sprockets