840 Automatic Float Switch, Style A Industrial Switch, Low Operating Force, Convertable for Tank or Sump Operation, Type 4 Fiberglass Polyester enclosure, 2 N.C. contacts 840 Automatic Float Switch, Style A Industrial Switch, Low Operating Force, Convertable for Tank or Sump Operation, Type 4 Fiberglass Polyester enclosure, 2 N.C. contacts