Low Cost Commerical PC Sheet Cover Material Multi-Span Greenhouses From China Factory. Durable Galvanized Steel: Constructed of hot dip galvanized steel tubes, durable and applicable for more than 15 years. Customizable Dimensions: Span, length, and roof height can be customized according to specific requirements. Versatile Cover Materials: Cover material options include PE/PO film, polycarbonate, or glass, customizable to needs. Advanced Climate Control: Equipped with internal/external shading, cooling systems, and wind/water curtain cooling. Multi-Span Efficiency: Multi-span structure better spans land use area and offers higher efficiency. Wide Application Scope: Suitable for cultivation of flowers, vegetables, fruits, and hydroponic seedling R&D.