There are many industries, such as manufacturing, mining or warehousing, that need equipment that can move heavy loads of 30,000 pounds or more. The heavy-duty bins and dollies that are being used for these purposes often need custom-designed wheels that can securely handle such extremely heavy loads. These industrial caster wheels are specially designed. They often have a forged iron core and a rubber or plastic tire. Rubber is perfect, when the surface is wet, since this material provides good grip and also helps to reduce noise. Another material that is often used for the wheel surface is phenolic resin. Industrial casters frequently have to absorb shock, for example when heavy loads get dropped onto the bins or dollies.