This is an OEM part sourced directly from the manufacturer. The flange nut is commonly found in Subaru/Robin engines. This part is made of metal, and is used in conjunction with a bolt and washer to hold the tank bracket in place. Please be aware that there are different nuts used in the machine. Refer to the parts diagram to be sure ...Read moreof ordering the correct part. You will require a wrench when replacing this part. This item is sold individually.