[Standard M12 Threaded Bolt] These swivel casters are equipped with a standard M12 threaded bolt, making them compatible with a wide range of equipment and applications [Heavy Duty 100mm Diameter] Supports up to 550kg per set, making our heavy duty casters ideal for easily moving furniture or heavy machinery - perfect for both home and industrial applications [Smooth and Quiet Rolling] The double ball bearing design ensures stability and effortless movement without noise or shock [High Stability and Safety] The double locking system of our swivel casters ensures stability maximum load and holds the wheel and swivel securely in place, preventing wobbling or movement of your furniture or appliances [Durable Quality] Made of impact-resistant polyurethane plastic, designed to withstand daily wear and tear and provide reliable service over time, while reducing the need for replacement parts