Damper, torque, rotary, spring & double action hinges are types of hinges to which loads are applied at the time when doors and lids are opened/closed. There are various types of hinges that offer various functions according to the application. Damper hinges allow doors to be closed slowly due to the friction of viscous material inside, and are used for food showcases and toilet seats. Torque hinges allow users to fix at any angle, and are used for connecting sections of liquid crystal panels and keyboards in notebook computers, etc. Rotary hinges can be fixed at any desired angle because torques are generated to both directions or to one desired direction. Spring hinges use the force of the springs in the hinges and operate to either direction, open or close. Double action hinges allow doors to be opened inward and outward, well known for Western swinging saloon doors.