These High Temperature Wheels are made from Glass-Filled Nylon. They perform best in moist heat applications such as in smokehouses, moist heat bakery and autoclave applications and around water and steam. Temperature Rating: Up to 425° F for 30 minutes MAXIMUM continuous operation. Then allow to cool to room temperature. If used above 425° For for more than 30 minutes continuous operation it will reduce the life of the wheel. High Temperature Glass-Filled Nylon wheels are not recommended for dry heat applications because once the moisture content of the wheel gets to zero, the wheel will shatter. 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.