high-low water alarm

例句：

1. 1.The high-low water alarm is an essential tool for flood prevention.
   高低水位报警器是防洪必备的工具。
2. 2. The low-level alarm system can detect the leakage of water in the pipelines.
   低水平报警系统可以检测管道中的漏水。
3. 3. The high-low water alarm helps us to monitor the water level in the reservoir.
   高低水位报警器帮助我们监测水库的水位。