We take the natural charm of Doug Fir tongue and groove siding and factory machine finish each board in this beautiful Black Oak stain. This stain gives the wood a rich dark brown color and still allows the natural wood grain to show through. When the stain is machine applied to all six sides, it protects the wood against moisture and harmful UV rays. The oil in the stain penetrates the wood and protects more than just the surface of the board making it water repellent with a beautiful rich finish.