Vtg Original Style 7" Ball Muffler Hit Miss Gas Engine 2 Inch . the actual od of the Muffler looks to be about 6.5 inches. Please see all the photos for the condition.  There are small holes in the muffler. It looks like it was modified.  It came off an old case tractor. There are no threads.  If threads are needed, you would have to cut off the coupler and weld on a threaded coupler. What you see is what you get. Thanks.