The Chirper Kit remains silent until the lights go out (just like a real cricket). The moment it gets dark the "Chirper" starts to make its racket driving your guest crazy. Of course, when your guest turns the light on to look for the "Chirper" it becomes quiet again. This fun kit features a CDS cell circuit with 2 transistors, piezo speaker and a flashing LED (which can be disabled). The built-in sound control allows you to adjust the sound from that of a crazy cricket to that of a chirping canary. Operates from 9V battery (not included). Size of board: 3" x 2". Complete with all parts, PC board and instructions. Skill Level 1. This kit requires soldering of components to the PC board while building.