The S-Max BOW300 is not just a blow off valve, it is a
musical instrument. It has one of the most unique customization
features in the market. With a simple adjustment (no tool
required) you can change the blow off sound of your turbocharged
engine: from an ear piercing whistle to a more subdued whoosh.
The BOW300 has small ports that change the resonance of the blow
off air depending on their alignment.