The Speed By Design CNC Blow-Off Valve Adapter Flanges allow you install Tial or TurboSmart Blow-Off Valves to your factory piping.
Your factory piping uses a 1G DSM Style BOV Flange which provides very limited aftermarket options, most of which are expensive as they are proprietary to the R35 GTR.
These universal adapters allow you to install a 50mm Tial Q/QR or TurboSmart Raceport Series BOV.
Sold as a quantity of (2) per vehicle.