All windmills now use a membrane air diffuser assembly instead of air stones.
The windmill price below does not include tubing or air diffuser. Select the type of tubing you prefer - both weighted (easy to install) and non-weighted are available. Due to the large air volume of the WM12N, WM16N, WM20N, & the WM25T, the airline has increased to 1/2" tubing and the air diffuser is now the double diffuser. This allows maximum air flow with increased oxygen and circulation rates.
