eighteen components are listed in the schematic for this Ls650p 1999 (x) (e02 E04 E17 E18 E22 E25 E53 / P37 Rear Swinging Arm .
On this parts fiche the Washer(10.5x28x2.3) is the most specified component.
The lowest price component in this Rear Swinging Arm parts-list fiche is the Bolt.