This is an OEM part sourced directly from the manufacturer. The locking washer is designed for use in Ariens garden tractors. This part is made of metal, and is generally used to prevent the inadvertent loosening of screws or bolts. Please be aware that there are different locking washers used in the machine. Refer to the parts diagra...Read morem to be sure of ordering the correct part. You may require a screwdriver or wrench when replacing this part. This item is sold individually.