Attaches to gas inlet nipple on soda keg via 1/4" i.d. tubing. An excellent way to instantly carbonate beer or wine with a minimal amount of effort. Just increase regulator pressure slowly over 2-3 minutes and your product will be carbonated. One of our own personal favorite products. Includes carbonation chart based upon product temperature. Requires 1.5 feet of 1/4" i.d. tubing to attach stone to keg. Can also be used for aeration. Made of stainless steel.