This Empire series glasshouse/greenhouse, uses the same structure as the Hexagon Series. It has become the strongest greenhouse we carry. This glasshouse is built with Super Strong Aluminum Connectors (2.5MM) and Exclusive Ultra Heavy Duty Box Section Aluminum Profiles (65 X 65MM) with our sophisticated bar-capping glazing system-NO SILICON REQUIRED! Polycarbonate sheet (8-10MM) or tempered glass (4MM) can be served for this new model greenhouse. The panels are retained neatly with a substantial aluminum external gasket and the edges of the panel are completely concealed. The sophisticated of our bar-capping glazing system is much stronger and neater than other greenhouses using similar bar-capping methods, as the use of silicon and PVC strip locking is not required in our models. What's more, all the bolts and nuts are invisible in this model. Thus, this greenhouse looks extremely neat, elegant and top grade.