Also called a hinge hinge is used to connect two solid and allow them to rotate relative to the mechanical device. The hinge may be composed of a movable assembly or a collapsible material. Main hinge installed on the door or the window and hinge installation in the cupboard, classified according to the material is divided into, stainless steel hinge and iron hinge; to allow people to enjoy a better and the emergence of the hydraulic hinge (hinge damping), its characteristics is bring the buffer function when the door is closed, and the greatest degree of reduce the noise made by closing the door and the cabinet body collision.