Description: Material: made of high-strength aluminum alloy and high carbon steel,the aluminum alloy crank adopts an arched structure to reduce the weight and increase the speed more quickly while ensuring the strength. Burly and lightweight crankset has better strength and reliability. Application: Suit for 8/9 speed, fit for mountain road bike, fixed-Gear Bicycle, Folding Bike and so on. High-carbon steel one-piece stamping, adapt to a variety of harsh environments, optimize the gear chain, and make the speed more efficient. Three-disc detachable disk nail locks the gears, which is convenient for replacement and reduces maintenance costs. Specification: Material: Aluminum Alloy, High Carbon Steel Size Chart: Crank Length: 170mm/6.69 inch Package Includes: 1 Piece Bike Crankset 1 Piece Crank Arm Note: 1. Please allow slightly error due to manual measurement. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! 3. Wish you a wonderful on-line shopping!