Notes: w/Fed Emissions; Reg Duty Muffler; Optional; HD for 22100;If welded Assy, replace all Reqd parts; Reg Duty Muffler; Optional; HD for 22100;w/Fed Emissions; HD Arc-welded construction, recommended for commercial use; HD Muffler.;HD Arc-welded construction, recommended for commercial use; HD Muffler.