Use this pencil jet when you want more water flow out of your Euro brush.
Change out or add in addition too...Your choice!
You can add these to your existing brush or replace your existing pencil jets with these jets that flow more.
In some cases you may wich to shorten the side that is installed into the brush so that the tip does not extend through too far, this depends on the thickness of the brush you are using.
Use a 13/64 drill bit to drill a new hole the brush.