It folds the system for folding type door, allowing the door to open like a book, so as to take up as little space as possible. The door, once opened, should be to clutter with the wing folded, the passage of the door space, reducing it. The door divided in half, centrally and symmetrically. This solution lends itself to environments not too spacious where necessary to limit the wing dimensions, which on the contrary is the case with the traditional solution with hinged doors. I fold the doors have retractable center hinges.