This kit is a rain detector circuit, working on the water falling onto the conductive strips on the PCB, which then, set off an oscillator in the transistors, which then, turns ON the speaker and LED. After you wiped the water on the conductive strip's surface, the Speaker and LED are turned OFF.
This is a solderless kit (Great For smaller hands or limited mobility)
Technical Specifications
Power Supply: 9VDC
Current Consumption: 28mA.
PCB dimensions: 2 x 1.5 in.