Hign-concerned Chemical:None Installation Method:Assembly Origin:US(Origin) : Upgraded 20'x10'x6.6' Large Walk-in Greenhouse Outdoor, Heavy Duty Galvanized Steel Frame High Tunnel Green House w/ PE Cover 2 Zipper Screen Doors, Gardening Plant Hot House 20 Stakes Green About this item ? 2 Independent Mesh Zipper Doors 8 Exhaust Vents? --- 2 Doors on each side of the greenhouse, one mesh door to keep small things out and ventilate on hot days; one PE cover door to keep warm. 2 Doors have independent zippers, convenient to use each door according to your need, and increase the greenhouse's functional quality. 8 exhaust vents for cross ventilation and venting. ?7 Rows of Crossbars?--- 3 Rows of crossbars on the top of the greenhouse, completely round structure, can prevent the snow and water from accumulating. Also the ground frame, with using the U-type stakes, will be effectively grip the ground and reduce the wind obstruction. ?Windows with all sided velcro?--- All sided Velcro on the windows can make the greenhouse air-locked and keep the inner temperature in winter, and all 8 windows have gauze mesh to keep things out when venting. ?Reinforced Mesh PE Cover?---heavy duty 2 layers PE cover with reinforcement mesh into it. 100% waterproof, transparent cover can get 85% of the sunlight through, at the same time it can prevent ultraviolet ray, won't make plant burned. ? Service We are here to help before and after purchase. We are here to serve your needs. Shipping We ship all items within Standard Shipping in 3 - 10 Working Days. If for any reason there is an issue with your order we will contact you right away. On the contrary, if you have any questions about your order, please feel free to contact us at any time. We will provide you with good solutions. There are issues that require friendly communication to resolve. God will bless every kind customer. Our small store will also be grateful. :) Carrier: UPS, USPS, FedEx. Returns Policy We have 30 days Money back returns policy. If you receive a manufacture defective item and want to return or exchange it there is no restocking fee. You don't pay more fees for a return.