The Shim,t=0.3mm is the lowest priced item on this Engine Mount schematic.
Parts such as the Engine Mount: Mount-engine, Bolt,10x25, Bolt, Shim,t=0.5mm are included in the Js800-a8f Jetski800 Sx-r 2008 Usa Engine Mount parts fiche.
Check out any of the eleven Engine Mount components enlisted.