Which one??There are two used, both are copper,both are the same size, and they are available at any auto parts store.Ya just have to file em a tad in the center so the plug will fit thru em.I've already had to replace one,but not because there was somethin wrong with it!! I dropped it and couldn't find it!! DUH!!! And when ya put em back on,make sure the surface on both sides of the copper washer,as well as the surface on the block they mate with,are CLEAN!!And do NOT OVER TIGHT EM cause you'll strip the threads and that's when your headaches will start.Snug em,then a tad more,and you're done!! Ca pishe???