Steel calf shelters made from old tanks( contents were non harmful). Made of 1/4 inch, 3/16 inch, and some tops of the tanks were 1/8 inch thick. 10 foot long heavy wall pipe welded on top for easy moving. Pipe also welded in middle to hold sides together. Very aerodynamic and 27 foot long shelters can be moved with bigger skid loader. Vary in height from 4 to 5 feet.