Soss hinges are strong, safe and secure. When the door is closed the Soss Hinge cannot be seen or tampered with. When opened the Soss hinge pin is not removable. The moving pivot point remains inside the hinge during travel until the door is fully opened. This eliminates a potential pinch point on the back side of the door. When the Soss Invisible hinge is installed, it is firmly anchored in a deep, full mortise which assists the screws in supporting the door, assuring a stronger, more rigid installation. Soss Invisible hinges are designed to give dependable operation for years.