09-11 KTM 530EXC: FMF Powerbomb Header With Mid Pipe (Stainless Steel) The redesigned PowerBomb is a four-stroke header that incorporates FMF's patented PowerBomb module at a precise location in the initial stage of the header. By positioning this "Bomb" at a key point in the system, increased performance and flow is achieved through the expansion and contraction of exhaust sonics through the system. Result is a flow increase of nearly 10%! The outer chamber in the Power bomb allows the air to expand, cool and ramp back up at a higher velocity. Additionally, the PowerBomb is a "pre-muffler" of sorts which helps to lower the bike's sound output by providing more sound absorbing surface area for the sound medium (exhaust gases). On some models, choices can be between a moto or super cross version.