Regular Harmon Style Hinges allow the door to align with millwork to essentially disappear into the wall when open. This Concealed Harmon Style Hinge goes one step further in hiding the mounting plates underneath a layer of millwork. Allowing the door to sit in a pocket of the wall creating a concealed panel, which does not project beyond the face of the door and creates a clean aesthetic. This unique hinge is a "swing clear" type of hinge that allows a door to swing into a pocket at a right angle to the door frame. When the door is in the pocket it is completely clear of the door opening. Ideal for closets, hallways, libraries or bedrooms to create consistent transitions throughout the residence. Features positive positioning stops at 0°- 90° standard, eliminating the need for a visible ball catch in the header. Hinge is not handed, they work on both Left Hand swinging and Right Hand swinging doors. Full mortise installation. Click on links below for more installation and dimensional information. Designed for 1-3/4" thick doors, other door thicknesses are available as a special order. Maximum door swing is 90 degrees with this type of hinge. Door Height Guidelines & How Many Hinges To Use: For doors up to 5 feet tall use 2 hinges. For doors up to 7.5" feet tall use 3-4 hinges. For doors up to 10 feet tall use 5-6 hinges. For doors up to 12.5 feet tall use 6-7 hinges. For doors up to 15 feet tall use 7-8 hinges.