The Pro Circuit R304 Shorty End Cap Silencer features 304 stainless steel end caps and intake tube. Extruded 6061 T-6 aluminum short housing with brushed finish. Lightweight, with high strength steel rivets and steel Allen head screws on 1 end for easy disassembly and rebuilding. The Pro Circuit 304 Factory Sound End Cap Silencer is constructed from the same materials as the Shorty End Cap Silencer. Longer aluminum housing for added top end performance. TIG & MIG welded for added strength & durability. Pro Circuit Pipes are tuned specifically for the year & make of the bike to achieve a performance gain in the areas that your stock pipe is lacking. Pro Circuit does not produce many different pipes for a single model bike, they make one pipe that performs well in all power ranges. The only difference between the Platinum & the Works pipe is the finish.