Six different specifications allow you to choose the most suitable one according to your needs. The galvanized surface makes it very rust-resistant and corrosion-resistant.Simple and convenient installation steps will not waste your energy and time. Professional and exquisite workmanship makes it very wear-resistant and durable.Made of carbon steel material, it is very durable to use.The inner diameter of the flywheel teeth is 3.4cm and the inner diameter of the fixed ring is 3.2cm.It is very suitable for a dead fly bike.Item Name: Bicycle Flywheel TeethMaterial: Carbon SteelFeatures: Wear-resistant, Heat Treatment, Anti-rustSize Details: Flywheel Teeth Inner Diameter: 3.4cm/1.34" (Approx.)Fixed Ring Inner Diameter: 3.2cm/1.26" (Approx.)Notes:Due to the light and screen setting difference, the item's color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Bicycle Flywheel Teeth1 x Fixed Ring