Item Type: Bike Flywheel Material: High Strength Steel Gross Weight: 775g / 27.3oz Speed: 11 speeds Number of 11 Speed Teeth: 11, 13, 15, 17, 19, 21, 23, 25, 28, 32, 36T Package List 1 x Bike Flywheel 1Stable Characteristics: High temperature resistance, corrosion resistance, rust prevention, no deformation, high durability, good impact resistance. 2Hardening Technology: The bike flywheel is made of high strength steel, which adopts hardening technology and has greater wear resistance and durability. 3High Accuracy: This flywheel has high accuracy tooth shape, strong compatibility, which makes long term riding more possible. 4Hollow Design: Easily reduce the weight, reduce the riding load, and achieve a good balance between strength and weight, an ideal choice to reduce the weight of bikes. 5Easy Installation: Professional manufacturing, direct replacement of old or damaged flywheel, excellent accessories for mountain bikes and road bikes.