Universal casters are the so-called movable casters, which are constructed to allow horizontal 360-degree rotation. Caster is a general term, including movable casters and fixed casters. Fixed casters do not have a rotating structure, can not rotate horizontally only vertical rotation. These two kinds of casters are generally used in conjunction with, for example, the structure of the cart is the front of the two fixed wheels, the back near the push handrail is two movable universal wheel. Universal wheel is installed in the caster wheel bracket can be in the dynamic load or static load horizontal 360 degrees rotation. There are many kinds of materials used to manufacture the universal wheel, the most common materials are: nylon, polyurethane, rubber, cast iron and other materials. They are widely used in many industries and various fields such as mining, mechanical equipment, electronic equipment, medical equipment, engineering decoration, textile, printing and dyeing, furniture, logistics equipment, storage, turnover trucks, chassis, cabinets, equipment, electromechanical, clean room, production lines, large supermarkets and so on. According to its different uses, the bearing is divided into iron core, aluminum core, plastic core, size 1 inch to 8 inch ranging. Among them, the iron core, aluminum core is generally a heavy-duty bearing wheel, often equipped with brakes when used.