The Omron 61F-G3ND AC110/220 is a High/Low Level liquid level controller from the 61F series, running on 110/220VAC supply. It uses conductivity sensing between the probe and a common electrode — when the liquid bridges that gap, the internal relay toggles. Sensitivity is adjustable from 0 to 1.8kOhm, which means it'll detect most conductive liquids (water, weak acids, coolants) but won't false-trigger on a thin film or foam layer. The three SPDT relay outputs (2 Form C each) give you independent alarm-high and alarm-low contacts, so you can wire a single unit to both fill and empty a tank without a separate controller. Contact rating is 3A at 200VAC, adequate for pilot-duty solenoids, contactors, or indicator lamps. The maximum distance from controller to sensor is 1km — plenty for a remote tank farm or a well pump that's a quarter-mile from the panel. Termination is screw terminal, which is what you want out here in the grease: no tiny push-in connectors that corrode or vibrate loose.
Mounts on standard 35mm DIN rail — snaps on without tools, and the screw terminals stay accessible with the unit in place. No IP rating is listed, so keep it inside the enclosure; don't mount it where washdown spray hits it directly.