High Temperature Phenolic Wheels are made out of FIBERGLASS. They are best suited for dry heat applications such as powder coating, dry heat bakery ovens and dry heat autoclaves. Temperature Rating: Up to 475° F for 30 minutes MAXIMUM continuous operation. Then allow to cool to room temperature. If used above 475° F for more than 30 minutes continuous operation it will reduce the life of the wheel.They have a hard surface and should be used on smooth floor surfaces. If the floors are rough or if there are obstructions which will impact these wheels it will reduce the service life of the wheels. In any high temperature application it is always best to shield High Temperature Wheels from a direct heat intake source.