Tired of high prices at the pump? Fill up this Gas Tank instead and enjoy money well spent. This discreet dynamo, boasting a 650mAh battery and 3 variable voltage settings, promises to deliver the fun with its preheat function and sleek design, the Gas Tank is the preferred choice for on-the-go. 650mAh Battery 3 Variable Voltage Settings (2.8V, 3.4V, 3.8V) Preheat Function