Wheels come in all sizes and are used for an almost endless variety of applications that go far beyond the automotive sector. For example, industrial settings require special wheels that can carry super-heavy loads up to fifty thousand pounds. These heavy duty caster wheels are often custom-made from injection molded plastic or urethane. They can also be two-component wheels, e.g. with a grey iron core and a polyurethane tire. Industrial casters often have to be shock absorbing, because heavy loads are often dropped into dollies. Even short drops can put a lot of stress on the wheels. Compound materials are designed to absorb this shock. These industrial wheels don’t get noticed much outside of the engineering profession, but without them many types of manufacturing would not be possible.