4-inch concealed door with concealed stainless steel wooden door concealed door and hinge hidden hingeHidden design - Our hidden door hinges are specially designed to be hidden in view and not stand out when the door is closed. Our hinges mean that you can use this heavy-duty hinge, whether your door is left-handed or right-handed. This requires slotting, which is not a standard size, but it is more suitable for DIY hidden door projects! ! ! High quality construction - Our hidden door hinges are made of stainless steel to durability. Advanced technology, reliability and safety - the concealed hinge is made by integrated laser welding process, which has higher durability, bearing capacity and wear resistance. Additional built-in gaskets and sealed bearings that the installed door can be opened and closed quietly. Before installing the hinge, the leaves move too freely, causing a collision sound. After installation, the door and frame provide necessary support and restriction for the hinge to that the leaves move smoothly and silently. Easy to install - the hidden hinge is also equipped with 304 stainless steel screws. The high-density self-tapping screw and the hidden hinge of the door complement each other, and the threaded hole and the screw go back and forth, so that the bite is not easy to loosen and deform. Widely used - stainless steel wire drawing. Our hinges are suitable for wooden doors, swing doors, secret doors, aluminum doors, fire doors, smoke doors, sound-proof doors, security doors and so on. Colour:Black Material:Stainless steel Package Contents: 1 * hinge 8 * screw Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.