Part # 1275 is an Aftermarket Replacement Muffler, by Rotary Corp. This Aftermarket Replacement Muffler has a 3/4" NPT Threaded Mount. This Muffler was designed by Rotary Corp to be used as an Aftermarket Replacement for B&S Part Numbers: 294599, and 294599S, for use on their Models: 9, 9B, 9F, 9R, 100200, 130200, 131200 170400, 170700, 171700, 190400, 190799 and 1954 Series of Horizontal Shaft Outdoor Power Equipment Engines.