BOV boost pressure relief valve AMAZING SOUND EFFECT !!! Protects your turbo !!! The standard DV valve forces the air into the circulation, while the Blow Off valve - the atmospheric valve lets the air out, which protects your turbo, and at the same time produces an amazing sound effect - characteristic PSSSSSTT !!!! High quality. Dimensions: Inner diameter of the inlet (plunger): 28mm Outer diameter of the outlet: 29mm. Bolt spacing: 105mm. Boost pressure relief valve BOV AMAZING SOUND EFFECT !!! Protects your turbo !!! The standard DV valve forces the air into the circulation, while the Blow Off valve - the atmospheric valve lets the air out, which protects your turbo and at the same time the occasion produces an amazing sound effect - characteristic PSSSSSTT !!!! High quality of workmanship. Dimensions: Inner diameter of the inlet (plunger): 28mm. Outer diameter of the outlet: 29mm. Spacing of fixing screws: 105mm.