The Omron 61F-G1H AC110/220 is a High/Low Level liquid level controller from the 61F series, running on a dual-rated 110/220VAC supply. This is the chassis-mount version with screw terminals — no DIN-rail adapter, so plan for a panel backplate or enclosure floor mount. Two SPDT (2 Form C) relay outputs rated 5A @ 220VAC handle the pump-up/pump-down or alarm logic; the sensitivity adjustment spans 15kOhm to 70kOhm, which covers most conductive liquids from tap water to weak chemical solutions.
The 50m maximum distance between controller and sensor probe means the 61F-G1H can sit in a central panel while the probes are out on a tank farm or sump pit — no need to locate the controller at the vessel. The sensitivity range (15kOhm to 70kOhm) is the resistance threshold at which the relay trips; lower-resistance liquids (tap water ~10kOhm) need the low end of the range, while higher-resistance liquids (distilled water or dilute chemicals) need the upper end. If your liquid is outside that band, the controller won't detect level changes reliably.