Premium Quality: This crank arm is made of premium aluminum 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 features excellent manufacturing with fine polish and durable paint, offering stable performance and a stylish appearance that enhances your bicycle's look. Standard Cutting: This bicycle left crank arm has standard precision cutting for the hole, making it easy to install and ensuring a perfect fit. The 170mm crank arm length allows no overlap between the crank arm and chainring bolt, making it a suitable replacement for bike repair. Great Replacement: Size: approx. 21 x 4 x 3cm / 8.27 x 1.57 x 1.18in. This 170mm bicycle crank arm is compatible with various bike models. Available in two models and two colors: black with square hole, black with rhombic hole, silver with square hole, and silver with rhombic hole.