We developed the PowerCore4 to increase the horsepower and torque throughout the entire power curve and give you a noticeable power increase that is very usable and beneficial, no matter what your riding style or ability is. Features: • Space Age internal packing for maximum packing life • Hi-Flo modular end cap • Internal shape of core uses Hi-Flo technology • Enhanced sonic evacuation provides for higher flow and increased power S/A: Spark Arrestor