Features: Made of high-strength aluminum alloy with smooth surface, it is durable, easy to operate and not hurt your hand. With chromium-molybdenum steel shaft, which has high strength, good toughness, high temperature resistance, corrosion resistance and impact resistance. The positive and negative tooth design of the chainring prevents the chain from falling, suitable for 8/9/10/11/12 speed mountain bikes. Crank Length: 170mm, Chain Ring BCD: 104mm. Easy to install and remove.