Elenco Sound Activated Switch Soldering Kit [ SOLDERING REQUIRED ] Hone your DIY soldering techniques on the Sound Activated Switch Soldering Kit; Enjoy the pleasure of having assembled and soldered it yourself Clap your hands together twice and watch the Sound Activated Switch turn on the light emitting diode (LED); Clap twice more and watch the LED turn off A monostable multivibrator, is a circuit that, once triggered, will switch its output logic level This is the core of the Sound Activated Switch Includes: PCB, electronic components and instructions PCB measures 639mmX1103mmX16mm Add this kit to your STEM curriculum From the company that brings you Snap Circuits - 9 volt battery not included