Hinge for the mutual engagement of panels composed of two opposed wing-like elements (1, 2), each of them including a basic body provided with through-holes for housing fixing screws to a panel and with engagement means with the wing-like complementary element provided at a lateral end of said basic body, at the end of the mutual engagement area locking means (3) for engagement of one wing with respect to the other are provided, characterized in that the former of said wing-like means (1) includes a basic body (14), having a rectangular trapezium profile, the end opposite to the vertical side of which being rounded in order to house a round-profiled cavity (15) therein; the latter of said wing-like means (2) in turn includes a basic body (23) having a partially polygonal and partially rounded profile at the engagement end with the complementary wing-like means (1), said rounded portion making up a cylindrical body that about halfway through along its height tapers to form a pin (23); the locking element (3) provides engagement and manoeuvring means on the outer surface and sealing engagement means of said wing-like means.