Wireless gong to extend existing door intercom systems or bell buttons. Consists of a transmitter with a 25cm connection cable and a gong unit with a Euro plug for the socket. The transmitter is activated by a potential-free button contact or by a 12V DC signal of at least 30mA. Gong unit with a 4-LED flashing light and optional gong tone (max. 85dB(A)/0.3 m). A total of 24 melodies, selectable for each transmitter. 4 adjustable volumes or silent signal only via flashing light. Radio range up to 200m (outdoors). Power supply: Transmitter: 1x 12V MN21 alkaline battery (included in delivery, only required for potential-free button activation) or 12V DC signal, gong unit: 230V, 50Hz. Housing dimensions: 34 x 88 x 20mm (transmitter), 80 x 87 x 28mm (gong unit, housing without plug). Set can be expanded with any number of additional FD2G gong units. In addition, up to a total of 8 transmitters (including FD2K bell buttons or FD2B motion detectors) can be registered to one gong unit, but please note the radio range.