Used brewed beer carbonization. The zero Micrometre stone is optimal to power carbonate your kegged beer, or as an aeration stone before fermentation. Colour: silver Material: stainless-steel Size: about 48*7*12mm Package Contents: 1 x 0 Micrometre Oxygenation Stone Only the above kit content, other products will not be included. Note: Light and varied reveals could cause the color of the thing in the photo a piece various from the real thing. The size allowed error is +/- 1-3cm.