Turck Safety Sensor MK91-12-R-24VDC Multi Modul Conductive Liquid Level ControlTurck Safety Sensor MK91 12 R 24VDC Multi Modul Conductive Liquid Level Control Used, working condition, pulled from surplus panel no longer in use. Has some dirt on it that got a bit stuck there when we used the wrong electronics parts cleaner. Cosmetic only, the units are guaranteed functioning 100% as pictured. Jumper wire from port 1 to 3 light up the switching status light, which is what happens when the liquid level designed point is reached.