High-strength stainless steel: This hidden door hinge is made of thick, sturdy stainless steel, ensuring durability. The specially treated surface coating provides excellent corrosion resistance and aesthetic appeal. Its superior design makes it ideal for a variety of hidden and side-hung door applications. Smooth and quiet 360° rotation: When the hinge is installed in the center of the door, the door can rotate 360°; when the hinge is installed on the side, the door can rotate 180°. Whether you are creating a secret room, installing a hidden bookshelf, or upgrading a door, this pivot hinge can meet your needs. Wide application: This door hinge kit has a unique upper and lower link construction, supported by a lower arm and base, which effectively reduces the load on the door frame. Suitable for various types of hidden doors, it is ideal for bookshelf doors, shelf doors, cabinet doors, panel doors, and more.