S&S Cycle 550-1000 Diamondback 2-1 Exhaust System Stainless Steel Four exhaust bungs for easy O2 sensor installation and air/fuel monitoring Full stainless steel exhaust system with stainless steel header pipe heat shields Oversized stepped header primary tubes for optimal flow and performance Header length helps your M-Eight motor make excellent power 4" OD diameter stainless steel muffler ends before the rear axle Computer aided design & precision bending for improved ground clearance Made in the U.S.A.