The Toughsonic Ultrasonic Sensors measure level and distance through the air using ultrasonic sound waves. They provide fast, reliable non-contact measurements at distance. These sensors come standard with 316 stainless steel housings, ruggedized piezoelectric ultrasonic transducers, epoxy potting, rear status indicators, and a permanently attached 2 meter cable. They are rugged and IP68 immersion-rated for use indoors and out.