... 2.Ac or Dc power supply optional 3.Apply to all kinds of medium 4CE.UL.RoHS Ultrasonic water level ... principle: the probe launch a bunch of ultrasonic pulse to the object, ultrasound is reflected by the object surface, ... dust, smoke, electromagnetic interference, strong corrosion etc. Widely used in chemical, petroleum, metallurgy, coal, building materials, paper making, environmental protection ...