The KidWind Power Output Board V2.0 includes a visual voltmeter, LEDs, resistors, a capacitor, and an AC-to-DC bridge rectifier. This device makes it very easy to demonstrate and measure the power output of your small wind turbines or solar panels. The bridge rectifier allows for the use of the Power Output Board visual voltmeter with a SimpleGEN generator. This board is included in the Basic Wind Experiment Kit and the Advanced Wind Experiment Kit as well as the Classroom Packs. No replacement batteries needed.