Used brewed beer carbonization. The 0 Micrometre stone is perfect to pressure carbonate your kegged beer, or as an aeration stone before fermentation. Colour: silver Material: chrome steel Size: about 48*7*12mm Package Contents: 1 x zero Micrometre Oxygenation Stone Only the above kit content, different merchandise should not included. Note: Light and various displays may cause the colour of the article in the photo barely various from the genuine thing. The measurement allowed error is +/- 1-3cm.