Medium and heavy double bearing series casters, with 3 "~ 6" wheels and a bearing range of 80 ~ 330kg, are widely suitable for various working conditions with medium and heavy load requirements. The casters are installed in top plate type, top hole type or screw rod type. The wheel materials are polypropylene wheel, polyurethane wheel, nylon wheel, high elasticity rubber wheel and artificial rubber wheel. According to the structure, they can be divided into universal wheel, directional wheel and universal belt brake wheel.