Includes chime, mounting plate, metal disk, and mounting hardware.
A small round magnetic disc is connected to a rod and the magnet attaches to a metal disc (which is attached to the frame or door) when the door is closed. The rod that is connected to the magnet is pulled off of the metal disc when the door is open, and the other side of the rod hits a metal plate (like one from a xylophone), which causes the chime sound.