These custom regulator vented plugs are a perfect example of the large number of custom automotive hardware components we supply our customer base.  We worked with the customer through a number of design iterations to forgo an initial design that included a brazed component and instead go towards a design shown here with a vented hole.  The socket recess provided another challenge – going with a broached alternative would provide a better cost profile but add risk of excess material affecting the vented hole.  Instead we decided to take on the additional cost and run a cold headed process for the recess, providing a clean look and application to the part.