Package Included- The hidden door hinge set included 1 set heavy-duty pivot hinge with 30 screws, which with top and bottom hinge; 1 ball catch hardware with 4 screws; 1 screwdriver.Easy to Install- The hidden door hinge is equipped with a telescopic pin for adjusting the up and down telescopic distance, easy to install. The pivot hinge is installed on the central axis of the door or installed on the side of the door. If you feel that the gap is too large, you can dig a groove of the door.Wide Application- Hidden door hinge is a unique upper and lower link design structure, supported by the lower arm and floor, thereby reducing the pressure of the frame. The invisible door hinge is suitable for various types of invisible doors, such as very suitable for bookcase doors, bookshelf doors, cabinet doors, panel doors.High-Quality Material- The hidden door pivot hinge is made of 304 solid stainless steel material, which is more sturdy. The surface is specially treated to prevent rust and breakage, fine workmanship, and improve its service life.360 Quiet Rotation- The pivot hinge is installed on the central axis of the door, and it can rotate 360 degrees flexibly and quietly in linkage with the upper and lower parts. The hidden door hinge shaft can rotate at multiple angles to achieve a high-end and outstanding hidden effect.570lbs High Load-Bearing- The hidden barn door hardware kit with high load-bearing design, the base support up to 570 LBS/259 kg. The heavy-duty door hinges with improved pivot mechanism provide quiet, smooth and flexible door movement even under heavy pressure.hidden door hinge murphy door hinge kit murphy hidden door bookcase pivot door hardware pivot door hinge hidden hinges for secret door secret door bookcase heavy duty pivot door hinges door pivot hinge set hidden bookshelf door secret door swinging door hinge hidden door hinges for secret door