Carlo Gavazzi Dupline Fieldbus Sensor Proximity Magnetic, ⌀ 11mm ABS Housing, Built In Transmitter, 1x Channel, 8mm, Supply: Powered By Dupline. Non-powered Dupline® magnet-operated proximity switch with built-in transmitter. Available in ⌀ 11 plastic housing or with M 14 metal thread. Monitoring of open doors and windows in building installations.