This one on the .91 is a 3255A, same on the .61 below and right of it. Neither had any metal in them, the .91 is yet to be run, the .61 has been run on glow and then the Diesel head was put on. The standard "dustbin" muffler is a little loud for my taste but not bad. The .61 lost 200 rpm with the 3255A as a glow, no diff. with the Diesel. Go here and click on Silencers "http://www.mvvs-nl.com/index.html"