With the GC 171 wireless module, it is now possible to connect additionalcomponents for hold-open systems such as ceiling-mounted fire detectors and manual trigger switches to the hold-open system. There is therefore no need for separate cabling to these components. The system is eminently suitable for installations in listed buildings or for retro-fitting in existing buildings.The FA GC 170 wireless extension system has a general construction technique permit, it can be used on all GEZE hold-open systems and it has been tested in accordance with EN 54-25.