The cupped washer attaches to the tri-arc blade with the use of the lock nut. This part is an OEM from Ryobi and Homelite to be used in brushcutters and trimmers. It is made of metal and helps to keep the cutting tool in place. A wrench will be needed if this part needs to be replaced. This washer is priced as an individual replacement part.
This is an original Homelite replacement part. The lower drive shaft is designed by the manufacturer for use in trimmers. This part is made of metal, and is placed in the drive shaft housing to transfer power from the engine to the trimmer head. You may require a screwdriver and wrench when replacing this item. This part is sold individually.