1. Strong aluminum frame with gutter system, 2. 4mm UV protected twin wall polycarbonate sheet is light, strong, safe, and virtually unbreakable and easy to handle; 3. Galvanized steel base can ensure maximum stability of your greenhouse. 4. Double sliding door and two adjustable windows for excellent ventilation. 5. Easy to assemble and DIY per the assembly Instructions. 6. Aluminum fasteners, stainless steel screws and excellent stainless steel window opener. 7. No steel exept for the base, our greenhouse won't be rusty so can be durable. 8. Good package(5 ply carton,one color label on PC carton,each aluminum parts per poly bag). 9. For this big size, we will add roof strengthener and side strengthener bars.