The door board is made of double-layer especially thick colorful steel plate to make sure intension of the door with large span. Wireless remote control or button on control box can ensure the door is exact in its position. It will start-up the automatically protection system , if the chain was broken by accident. Infared monitoring will make the door stop automatically during its movement if any objects are getting across. The window can be designed on the door board to make sure sufficient light inside the room.