LEVEL INDICATORS, these light portable apparatuses serve to water level measuring in bores, wells, and water basins 10 to 100 m in depth. The numeral character behind the type symbol indicates band legth used to measuring. The measuring probe contact with the water lebel causes indicating illuminative diodes blinking jointly with an acoustic signal sound. In the case of bore depth measuring extension piece application the probe contact with the water lebel causes indicating illuminative diodes blinking jointly with an acoustic signal sound and the probe lump down to the bottom result in illuminative diodes switch off and signal stop as well. Required water minimum specific conductivity is 50 µScm-1.