The Washer is the cheapest item from this partsfiche.
This schematic depicts all components used in the Gsxr1000 2006 (k6) Usa (e03) Water Pump partslist.
Parts such as the Water Pump: Impeller, Washer, O Ring,water Pump Holder, Gasket(6x15x2.2) (nas) are included in the Gsxr1000 2006 (k6) Usa (e03) Water Pump parts fiche.