Material: Galvanized iron Color: Silver Ball material: Nylon Ball diameter: 16 mm (0.63 inch) and 25 mm (0.98 inch) Dimensions: 48 x 32 x 20 mm (L x W x H) for 16 mm; 75 x 50 x 30 mm (L x W x H) for 25 mm Package includes: 4 x roller transfer units 8 x screws - Delivery content: 4 nylon furniture casters, 8 screws, 16 mm or 25 mm round ball transfer unit with compact installation space. Each unit features two mounting holes for secure screw attachment. - High-quality materials: The ball transfer unit body is constructed from galvanized carbon steel, offering resistance to scratches, corrosion, and rust, ensuring durability and long-term performance. - Comfortable and practical: Designed for smooth operation; the ball rotates 360 degrees freely, enabling effortless movement of goods and improved efficiency. Each caster supports up to 15 kg, suitable for a wide range of applications. - Quiet operation: Roller ball bearings are polished during manufacturing, resulting in a smooth surface that ensures quiet and seamless rolling with minimal noise during use. - Wide application: Ideal for moving items in both residential and industrial settings. Commonly used with sofas, display cases, carts, shelves, scooters, cabinets, kitchen appliances, conveyor systems, power equipment, processing machinery, packaging machines, and auxiliary devices.