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 minimum distance of 8 mm apart. The electric circuit of this NC opening detector is closed in normal state (NC). If the distance between reed and magnet increases, the circuit is broken and an alarm reported. The detector is tamper-protected and stray-field protected. Stray-field protection means that only the magnet belonging to this opening detector has the right field strength to keep the electric circuit closed. Any change to the field strength (e.g.: by another magnet) breaks the circuit and an alarm is triggered. 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. It is water-resistant and dustproof (IP 68). The opening detector is VdS certified and available in white and brown.