When the end caps and flanges are installed on our watertight enclosures, the air inside is compressed a bit and tries to push the enclosure open. This vent allows you to quickly and easily release the pressure and then seal things back up. You can also use it to vacuum-check your enclosure, ensuring there’s no leaks. It’s based on our standard M10 threaded bulkhead design with an added “plug” that fits in to seal it. The plug is sealed with double O-rings and screws into the bulkhead.