This product is suitable for retrofitting folding bikes, city bikes, and electric bikes. It supports variable speed freewheel, offering high axial strength and compatibility. With standard precision machining, it enhances chain retention, increases service life, and reduces friction. It serves as an excellent replacement for bike repair and upgrades, compatible with various bike models. The crank arm length is 170mm, ensuring no overlap between the crank arm and the chainring bolt. Colour: silver Material: aluminum alloy Package Contents: 1 * chain ring with crank 1 * crank Only the above package content is included; other products are not included. Note: Light and different displays may cause the color of the item in the picture to differ slightly from the actual item. The allowed measurement error is +/- 1-3cm.