Premium Quality: This 100 percent brand new crank arm is made of premium aluminium alloy material, which is lightweight and deformation resistant. It is not easily damaged, has reliable quality and ensures high strength for long-lasting usage. Exquisite Workmanship: This bike crank arm adopts excellent manufacturing process with fine polish and great paint, which has stable performance and stylish appearance and can add a unique look to your bicycle. Standard Cutting:This bicycle left crank arm with standard precision cutting of hole, which is easy to install and ensures perfect fit to bike. 170mm crank arm length without any overlap of crank arm and chain ring bolt, which is a nice replacement for bike repairing. Great Replacement: Size: approx. 21 x 4 x 3cm or 8.27 x 1.57 x 1.18in. This 170mm bicycle crank arm is compatible with many bike models, and it is available in 2 models and 2 colors ( black-square hole black-rhombic hole silver-square hole silver-rhombic hole ).