Blazing Star DA-170 Standoff - 0.5 inch (12mm) length with additional 2mm and 3mm Delrin spacers included. 

Blazing star mounts offer a convenient way to make up required mounting distance on your gas engine installations AND provide tremendous extra strength to your gas engine case in the event of a crash. Mount the aluminum blazing star mount directly to the back of your engine and use any necessary plastic spacers between the wood firewall and the blazing star mount.