Industrial casters can be divided according to whether there is a rotating structure:
Stem swivel casters and fixed casters. Stem swivel caster is commonly known as caster. Its structure allows 360-degree rotation. Fixed caster without rotating structure so it can not rotate. In most cases,the two kinds of casters are generally used together such as the structure of the trolley is two fixed wheels in front and the push armrest is two stem swivel casters behind.