(pat.) 4-point locking device for turn-first function, corner drive fulcrum. Basic kit with short arm in galvanized steel, LH concealed hinges made in black galvanized zamak and hight resistence white galvanized steel, corner drive and locking points in black galvanized zamak, 7 nylon bushings Ø 6-8 mm, screws in stainless steel AISI 304.