Magnaflow Muffler company has a test truck... it has 4 pairs of mufflers, on a rotating rig, and they call it the "Revolver"

the senior manager of Magnaflow thought if it, Chip Foose was brought in to work up the look, and SEMA was the debut. For more about it: http://www.streetlegaltv.com/features/sema-coverage/sema-2012-magnaflow-brings-the-revolver-to-the-show/