There are several different types of light caster wheel, different sizes, colors and styles. The most common type of chair caster is the twin wheel hooded caster, (Pictured right). The stem on this caster is a grip ring stem 7/16" wide or thick by 7/8" tall and has 50mm wheels (2"). Made out of black nylon. This style caster comes on most new office and desk chairs and for the most part is adequate for the job.
Our company is stem swivel caster manufacturer in china, here I want to take you visit our factory from these pictures as followings: