The idler pulley wheel provides the tension for a multi-ribbed belt and helps the belt to rotate the drum. The drum will not spin if the idler pulley fails to put the correct amount of tension on the belt. The wheel is white in color and is made of plastic. If the drum will not tumble, is noisy, or will not start, you may need to replace this part. This idler pulley is a genuine OEM part. Please remember to disconnect the power to your dryer before you start your repair.