Maximum operating temperature is 158°F (70°C). 4 inch fan is thermally protected and uses permanently lubricated ball bearings. 6 and 10 inch fans have ball-bearing construction and split capacitor motors. Split-capacitor motors are thermally protected to avoid premature failure. Dynamically balanced impellers molded from polycarbonate material. One finger guard is furnished (additional finger guards are available). All mounting hardware is provided. 240 and 560 CFM fans have ball bearing construction and split capacitor motors. Fans have lead wires with ends stripped 1/2 inch or 6 ft cord with polarized plug for power connections.