The exhaust itself is in two parts, the first connecting to the cat or de-cat pipe through a 3.5" bore 2 hole flange, this then converts into the 3.5" pipe work which leads to a 3.5" kakimoto 4 hole flange. The second part connects to the first part via a 3.5" kakimoto 4 hole flange, and continues through 3.5" pipe work into the muffler. Within the muffler is a welded in baffle where the bore of the baffle is roughly 2.25", which then opens into a 115mm exit tip.
The exhaust is marvellous when travelling on the motorway and there is no droning whatsoever, it's virtually like driving with a standard exhaust. This is perfect for someone who wants to improve their exhaust flow and performance without having to wake the dead!