The opening detector is a magnetic contact for protecting doors and windows. Unauthorised opening is detected and reported to the alarm center. The opening detector consists of a magnetic contact (reed) and a magnet. These are fitted parallel, in front of, or at right angles to each other at a maximum distance of 13 mm apart. The electric circuit of this NC opening detector is normally closed (NC). If the distance between the reed and the magnet increases, the circuit is broken and an alarm reported. The optimum installation location is the middle of the door or window frame. It can also be fitted to the bottom of the window frame if a particular window with a magnetic contact is to be tilted open. The detector is suitable for both flush and surface-mounted installation. The opening detector is available in white and brown.