We 're introducing a new look for all kinds of opening doors & windows, thermal insulated or not. With the hidden hinge concept, as mentioned by name, you cannot see the hinge on an opening door or window. Why should anyone use this ?? A. Much better aesthetics and window & door design B. Better performance window and door as perimetrical EPDM and elastic gaskets override the hinges giving better airtightness to the fenestration. C. Better in safety as no one can see where the hinges are positioned The patent is available to potential investors with a complete set of technical drawings for mass production