Thunderheader XSeries High Pipe 2 Into 1 Chrome Exhaust System Harley Softail M8Brand New Part # 1360X Thunderheader Softail Chrome X Series High Pipe 2 into 1 Exhaust System w Heat Shields Fits Harley 2018 and up Low Rider, Low Rider S, Softail Slim Our X SERIES Exhaust is our newest line in creating maximum horsepower. With our 2" headpipe, equal length tubes, and a larger collector, this exhaust is made specifically for Harley Davidson's Milwaukee Eight engine. Includes full coverage heat shields. 18mm and 12mm O2 sensor