The FS series is a unit manufactured by RWM company. It is s V-groove wheel that has s strength with a cast iron and a forged steel. Further, it is intended for groove operation. In various cases, it is applicable on irons that have one side. Also, it has an iron that is casted. It has a temperature range of 50° to 800°F and a lubrication fitting of standard 2-1/2" and wider wheels.