... Fixed Roof Vent.better natural ventilation.It is a good choice if your place is hot and wind not strong. SpecificationDataSpan Width8m ... systemShading SystemIrrigation System1. Features:Roof Vent, which is fixed, can be good ventilation on the top, especially suitable for hot ... 2. Structure1) Greenhouse built by hot galvanized steel pipe, is composed of column, arch, purline, lattice bar, gutter and ...