You can't control the weather, but you can have all-weather control of your greenhouse with our complete roll-up curtain system. Our system includes everything you will need for years of continuous operation. No lumber to purchase, no extra poly fasteners to purchase; our price includes everything. In addition, you can choose a manual crank or an incrementally automatic system. Our fabric is a heavy-duty 12 mil. coated 10'x10' weave fabric (not 6 mil. poly), strong enough to withstand the abuse of windy conditions and even rocks thrown by lawn mowers and weed-eaters. Growers prefer curtains that roll up from the middle as opposed to rolling up from the bottom; crank rotations are reduced by 50%, and curtains are kept straight. Affordable and easy to operate natural ventilation as well as adaptable to any greenhouse with straight sidewalls.