This is the highest flowing universal blow off valve. For use on turbo-charged and supercharged applications. The body and all internal components are CNC-machined from 6061 aircraft grade aluminium. 1.98 in (50.5mm) valve. 7mm vacuum / boost hose barb size. Flange is v band, and comes with a 2″ weld on pipe. Supplied with an 11psi spring, optional 6 or 2psi springs available separately.