High quality premium 64 mm open BOV with aluminum weld-on flange Precision Turbo PTE PB64 Race Blow Off Valve 64 mm High quality premium 64 mm open BOV with aluminum weld-on flange Precision Turbo open blow off valve comes with aluminum flange and connection fittings Made of lightweight 6061 and 7075 aluminum, PTE/s 64mm BOV is anodized matte black to be aesthetically pleasing yet functional and provide long-lasting protection from the elements. It features a Kevlar reinforced silicone diaphragm for quick response and a hard anodized valve stem for improved durability. The PB64 also features a CFD designed valve and valve body for highest flow even at low lift, while the attached O-ring seal prevents leaks. In addition, PTE/s PB64 BOV features an innovative and industry-unique wave spring that provides additional weight savings and keeps the valve closed at idle, even at high vacuum. PTE/s PB64 BOV is designed to release the back pressure created when the throttle valve closes via a spring-loaded valve-diaphragm assembly. It is a key component in preventing potentially damaging volume blowback back into the compressor to reduce wear on both the turbo and the engine. The PB64 comes with an aluminum weld-on flange and spring adjustment screw. Mode of operation: Open BOV