Description: Secure And Stable Performance: The 4 Wheel Trolley Assembly Roller uses deep groove ball bearings to make sure you can operate it smoothly without making any noise. Wide Application: Trolley Assembly 4 Wheel are suitable for large iron doors, wardrobe cabinets, household sliding doors, curtains, automation equipment, factory track pulleys. Light Duty Build: Our roller trolley assembly is made of iron material, that’s impact resistant and zinc galvanized to offer protection. Heavy Duty: trolley assembly is sturdy and reliable, impact resistance, smooth and noiseless, hard to break,withstand long term use. Versatile to Use: the chain hoist trolley wheel is suitable for a wide range of different usage scenarios and is perfect for mounting on a ceiling trolley system or electric lifts. Size Chart: 13cmx8.5cm/5.12inchx3.35inch Package Includes: 1 wheel Trolley Assembly Note: Please allow slightly errors due to manual measurement and different monitors.