D.I.Y. Lie Detector Soldering Practice Electrical Engineering Kit for BeginnersThis kit can be great fun at parties. Lie and an audible tone will change. The more you lie the louder the tone. When you lie your hands sweat. This kit allows you to measure these changes; only a very slight amount of change will cause the tone to increase in frequency. Power requirement 6 to 12 v DC. Size: 0. 8" x 1. 2". BEGINNER KIT: Requires little or no previous knowledge of electronics. Basic soldering techniques required for circuit board