Thank you for coming to our shop, I hope it is to your satisfaction Item Name: Bicycle Flywheel Teeth Features: Wear-resistant, Heat Treatment, Anti-rust Material : Carbon Steel Manual : no Size Details: Flywheel Teeth Inner Diameter: 3.4cm/1.34" (Approx.) Fixed Ring Inner Diameter: 3.2cm/1.26" (Approx.) Specifications: The inner diameter of the flywheel teeth is 3.4cm and the inner diameter of the fixed ring is 3.2cm. Made of carbon steel material, it is very durable to use. It is very suitable for a dead fly bike. You can choose the most suitable one according to your needs through its six different specifications. And it can be very rust-resistant and corrosion-resistant due to its galvanized surface. Featuring the professional and exquisite workmanship, it is very wear-resistant and durable. It has the simple and convenient installation steps, making it not waste your energy and time. Kindly Remind: Due to light and display, there may be slight differences between the picture and the actual color of the product. The color is subject to the goods received. In addition, please allow slight size difference due to manual measurement. High quality, assured choice is guaranteed Package Includes: 1 x Bicycle Flywheel Teeth 1 x Fixed Ring