73153552
Dec 27, 1977
Feb 24, 1981
Point and Continuous Level Controls, Level Control Probes, Level Detectors and Indicators for Use in Either Controlling, Detecting, Measuring or Indicating the Level of, or the Presence or Absence or Proximity of Liquids, Powders or Granular Materials in Vessels or Bins; and Parts Thereof
Electrical and Scientific Apparatus