【LEFT RIGHT CRANK】:104 BCD Mountain Bike Crank set weight: 675g, Crank length: 170mm，Hollow Integrated Crank Arm 。 【ALUMINUM ALLOY MATERIAL】:high-strength aluminum alloy 6061 material, strong and impact-resistant, uniform force, stable riding. 【GXP DIRECT-MOUNTED STRUCTURE】:Effectively improve the strength and reduce the weight,screw lock,which is not easy to fall. 【INSTALLATION TIPS】This crank arm is divided into left and right side, please pay attention to the left and right side when installing,R is installed on the right side. L is installed on the left side, If you install it wrong, it will not work. 【PACKAGING INCLUDES】： left and right cranks,screws,please check the size you need before buying.