Little Giant 513390 OS3-1 is an oil sensing unit for sump systems. It monitors the liquid that passes through the pump. It stops the pump when there is oil or other harmful substance entering the water system. It will monitor pumping systems with motors up to 1hp. The voltage needed to run this unit is 115V single phase. This Little Giant 513390 OS3-1 Oil Sensing Unit has multiple light indicators mainly for power, pump run, high-water, high oil, and pump overload. It has a remote alarm and an alarm panel which can be connected to the remote panel of this unit. Its remote panel contains audio/visual alarming. The main and remote panel of this Little Giant 513390 OS3-1 Oil Sensing Unit have auxiliary contacts for connection to a building’s automation system. It has an acrylonitrile butadiene styrene (ABS) housing and a stainless steel probe. For more details, you can refer to the specification sheet. This oil sensing unit is covered by a limited warranty for a period of 24 months. Little Giant has proven their excellence for over 70 years by producing reliable pump solutions, packaged system options, and accessories.