Level Watch III（LWIII）uses ultrasonic waves to detect the presence of water or other liquids in the cargo holds of bulkers and other dry cargo ships, as well as in other areas where it may be necessary to detect water ingress. Various mounting configurations for LWⅢ are available, but the basic functions of the detector remain the same. LWⅢ is mounted at a set point. When water submerges the transmitter and receiver in the probe, there is a change in the ultrasonic wave that reaches the receiver. This change activates the alarm.