Description: Made of premium aluminum alloy, CNC machined and electroplating process - bright, corrosion resistance, ultra-light but high strength Specifications: 45T 47T 53T 56T 58T; standard 130mm BCD; 170mm Crank Arms Narrow wide tooth design increase the contact area with the chain greatly Comes with 5 bolts for easy and convenient mounting Wide applied for Mountain, Road, BMX, Fixed Gear, Folding Bikes etc. Specification: Material: aluminum alloy Crank Arm: Length: 170mm Compatible: single 3/6/7/8 speed chainring Weight: about 525g (right & left) Chainring: BCD(Bolt Center Diameter): 130mm Diameter: 45T(195mm/7.7inch); 47T(205mm/8.1inch); 53T(225mm/8.9inch); 56T(235mm/9.3inch); 58T(245mm/9.6inch) Color: black Package Includes: 1 Set Bike Crankset (Chainwheel and Chainarm) Note: - 45/47T is fit for 14inch folding bikes, 16inch folding bike select the chainring less than 53T, and 20inch folding bike need the chain ring less than 56T. 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.