The sturdy metal structure is made of thick, high-quality materials, ensuring durability and strength. The surface is specially treated to resist rust and damage, with fine workmanship that enhances longevity. Base support up to 570 LB / 260 kg. Constructed with high-quality materials, excellent forging process, scientific structural design, and secure screw fixation. The hinge provides stable and strong support for the door. Up and down linkage function; hinge installed on the central axis allows 360-degree rotation, while side installation supports 180-degree movement, suitable for various configurations and applications. Precision-engineered base bearing design ensures quiet, smooth, and flexible door operation. Compatible with wooden doors and aluminum frame doors. Ideal for use in hidden doors, heavy-duty doors, secret doors, hidden door bookcases, bookshelf doors, swing doors, hidden shelf doors, and door hinge kits. Create custom hidden door solutions as needed. Installation is quick and easy with included hardware. Material: Metal Color: Black Package Contents: 1 set hidden door hinges Note: Light reflection and differences in display screens may cause slight variations in color. Measurement error allowance is +/- 1-3 cm.