This was the reply I received from the owner:
Thats my bike, built it a couple months back. That was a handmade silencer that looked cool but was just way toooo loud. Now I've got a pro-circuit shortened 6 inches. Not much longer than the one in the pic, looks better on the bike and sounds real good. We build dune bikes with the 16" rear fat paddle and 18" front fatty set-ups, using all stock components. The handling, control and traction is awesome.