This set includes the turned exhaust found on late NTS fitted aircraft, designed specifically for the new Trumpeter AH-1W kit. 

Parts come as shown in the product image, and only require a very light sanding to remove the support nibs on the mating surface. No modification of the kit is necessary, making this a literal drop in fit. 

CAD work by Peter Fidloczky, using personal photos and measurements from the FLSC Library, as well as Bell loft drawings.