Albion???s new MG wheel is made of neoprene -- a synthetic rubber material that provides a higher quality of resistance from oil and chemicals than stanrdard rubber. This material is used in thousands of applications in diverse environments. These wheels have very high resilience, are impervious to metal chips and screws, and have an extremely high chemical resistance. Load capacities of 500 to 700 lbs. The neoperene is attached to an die caste aluminum core. Its standard operating temperature range is -40??F to +180??F.