SuperTrapp's Fat Dual 2-into-2 systems feature 1.75" primary head pipes, completely covered by full length 2.5" heat shields. The staggered fitted cylindrical muffler bodies are 3.5" in diameter. Grooved end caps are included with these Fat Duals 2-into-2 systems. The end caps are removable and can be replaced by all SE Series and Kerker Slip-On end caps. This means that riders have the luxury to choose from 11 different styles of end cap. Fat Duals weigh 10% less than stock exhaust. Headers are equipped with O2 sensor ports and come with plugs to close them when fitted on models without O2 sensors. Fit all 1984-2011Softail models, except FXCW Rocker and FXCWC Rocker Custom.