Otlav 3D Concealed Hinge In300120vn02. Otlav Concealed hinges are the perfect solution when you want to show the design of your interior doors. These hinges are made of high quality corrosion-resistant material, which will allow this equipment to last a long time. They do not make noise when using the door. For an 80-inch plate, only 2 loops will be required to perfectly support the weight.