Our greenhouses high tunnels are made of hot galvanized steel pipes. It is very easy to assemble even without experience. All of the connect accessories are provided. Also you can choose to have side or roof ventilation for the greenhouses. The plastic covering is 3-ply extruded with anti uv formular. The available thickness: 100micron, 120micron, 150micron, 180micron, and 200micron. For more information about our greenhouses high tunnels, pls visit . Or you can contact us through the following ways. Emai . Skype: zoe_greenhouse. AOL . Cell number: 0086 13003913916. Looking forward to your inquiry.