High Quality Material: Made of AL7075-T6 aluminum, CNC machined process and anodic oxidation electroplating, with the trait of smooth surface, bright color, not faded and corrosion resistance. Elliptical Design: Eliminate trampling dead point, enlarge force distance for the best starting point, solve chain skipping problem, save more effort and increase speed, without any hindrance or noise. Knee protection: The chain ring can distribute trampling power more reasonably so that protect knee meniscus more effectively and reduce knee wear during climbing race and long-distance riding. Perfect for Folding Bikes: For 14/16/20in folding bicycles, 45/47T is fit for 14in bike, 16in folding bike usually select the chainring less than 53T, and 20inch folding bike need the chain ring less than 56T. Size of single speed chainring: Speed- 45T 47T 53T 56T 58T; Color- red, gold, silver, and black for you to choose. Please determine that your crank BCD specification is 130mm before purchasing. Specification: Material: AL7075-T6 aluminum Speed: 45T 47T 53T 56T 58T Color: Red/Gold/Silver/Black BCD130mm Diameter: 45T-192mm; 47T-200mm; 53T-224mm; 56T-235mm; 58T-245mm Package Includes: 1Piece Bike Chainring Note: The chain must be lengthened if the larger chain ring is replaced. When choose large chainring, please confirm that whether its diameter is within an appropriate range, otherwise it will need to replace a longer axle.