This keg lid features a ball lock gas post which is attached to a piece of food grade hose, that has a stainless steel 0.5 micron diffusion stone on the end of it. The stone will hang down in the bottom of your keg of cold brew coffee (or other beverage) and allow the nitrogen (or other gas you may be using) to infuse into your beverage from the bottom up. This makes infusing cold brew coffee for serving nitro coffee on draft much easier and faster than having to shake your keg.