Specifications: Made of T6 heat treated high strength aluminum alloy material, it is firm and durable. Bicycle chainring adopts CNC high-speed milling and engraving and hard oxidation treatment process. It has mud channel, which can discharge mud faster, reduce wear and tear, and it has low resistance and is easy to clean. The design of positive and negative tooth, one thick and one thin, it can reduce the gap between the chain and the chainring and can be tightened with the chain, greatly prevent the chain from shaking caused by speed change. Item Name: Bicycle Chainring Material: Aluminum Alloy Type: 30T/32T/34T/36T/38T/40T Features: Firm, Durable, Easy to Clean, Precision Finishing Diameter: 30T: 12.7cm/5", 32T: 13.5cm/5.31", 34T: 14.4cm/5.67", 36T: 15.2cm/5.98", 38T: 16.1cm/6.34", 40T: 17.5cm/6.89" (Approx.) Notes: Due to the light and screen setting difference, the color of item may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Package Includes: 1 x Bicycle Chainring