Even if there is no direct contact with the medium, aggressive vapours and fumes can severely affect the function and lifespan of a sensor. The sensor surface of standard units is unprotected and therefore susceptible to contact from media such as cleaning agents, coolants or lubricants. Full-metal ultrasonic sensors consist of a stainless steel housing and are thus protected from any influences. Even the connector is made of high-grade stainless steel. Thus, the sensor is resistant to external influences and benefits from an extended service life.