Smooth Internal grease, smooth operation, good mute effect. Service: If you encounter any problems during the use, please contact our customer service in time, we will solve any difficulties for you in time. DIY tool: The U-shaped sheave is the ideal DIY tool for the track of industrial automation equipment and camera equipment. Also suitable for motors, toys, models, instrumentation, power tools, communications equipment, fitness equipment and other fields. High quality: high hardness, high precision, high speed and high load. Premium material: The U-groove pulley is made of high quality Stainless Bearing Steel material, rust and corrosion resistant.