This is a genuine OEM part that has been sourced directly from Generac. At one end of the frame there are two wheels, on the opposite there are rubber feet there to support it. These rubber feet help keep the generator balanced, they help keep it in one spot, and they help to reduce vibration. A reduction in vibration leads to a reduction in noise also. These rubber feet are mounted underneath the frame, the nut used to secure the part is sold separately. The foot itself is made out of rubber; the threaded shaft used to secure the foot is made of metal. This replacement part is sold individually.