Epcos has developed two PTC components with stainless steel packages for sensing the level of liquids. The B59050D1100B040 type is suitable for measuring water levels and can be operated within a temperature range of between +10 °C and +65 °C. The B59050D1120B040 variant is designed for liquids with a thermal conductivity of λth >0.12 W/mK such as oil or fuel. The permissible temperature range in this case is between -25 °C and +50 °C.

To prevent overheating, the PTC elements should be operated at a voltage <18 V. The tip of the PTC element can emit different thermal losses. The transition from liquid to air and vice-versa causes these losses to change very quickly, and as a result, the resistance of the PTC element. This allows the device to record very simply and exactly whenever a liquid goes above or below a certain level.