3-wire connection technology (neutral conductor required). For switching lighting systems. For switching two independent load circuits. For controlling lighting and ventilation systems. Operation in two-way circuits possible via button extension. Operation also possible via conventional buttons (2020 US, 2021/6 UK). Without control element. For control element flex, 1-way, 64711 and Wireless, 62711-WL. For control element flex, 2-way, 64721 and Wireless, 62721-WL. For Busch-Komfortschalter® flex control element 64765-... . For Busch-Wächter® 180 flex sensors 6476x-... . For Busch-Wächter® 180 flex sensors, Wireless, 6276x-.-WL. For Busch-Präsenzmelder flex sensors 6475x-... . For Busch presence detector flex sensors, wireless 6275x-...-WL. Can be combined with extension insert flex, 64891 U. Only in conjunction with commercially available flush-mounted device boxes in accordance with DIN 49073, mount or Busch-Jaeger item no. 3040 flush-mounted box masonry, 3050 flush-mounted box hollow wall or 3060 flush-mounted box concrete)