Universal 40mm External Wastegate 4 Bolt Turbocharger Boost 20 PSI BOV H-Style SilverHigh performance stainless steel valve with bronze valve guide Silicone reinforced diaphragm for maximum life expectancy and heat resistance Ductile cast iron valve body to resist extreme temperatures and warping Valve body has fin heat sinks to help dissipate head and minimize heat on the diaphragm body Aluminum spring hat to prevent changes on spring rate due to heat allowing consistent power level All necessary gaskets and bolts are include (note