Loudvalves 2.5" Boost Activated Exhaust Cutout/Dump stainless steel bypass valve FULLY AUTOMATIC! No switches, No wiring, no electric motors to burn up, just hook up a boost reference line to the valve STAINLESS STEEL 304 Body will ensure years of troublefree use Opens at about 6psi of boost (can be opened at higher boost if desired with boost controller) 2.5" inlet and outlet.