A flag hinge is a piece of hardware used to allow movement of two pieces of material. They are commonly used on various types of doors to facilitate directional movement; the flag hinge itself is usually mounted on a vertical plane, thereby allowing horizontal movement of a door or other piece of material. The hinge consists of two parts: a male end with a plate and a pin, and a female end with a plate and a receiving slot. The two parts are joined together once each plate is secured to a different piece of material.