The keyword for the outdoor wood burning fireplace is clarity. Simple clear-cut lines and practical use are comprised of long-lasting and special material created for outdoor use which is almost pure carbon steel but processed to have a protective layer on the surface to make it weather-proof. The surface is originally reddish-brown (resembles the colour of rusting), which becomes darker within time. If used properly, Cor-Ten steel is expressive, durable and maintenance-free and can stand the time in its own peculiar way.