380mAh Preheat VV Battery & USB Charger 380mAh preheat variable voltage battery with plug in USB charger. Standard 510 threading will fit nearly any cartridge on the market. Turn the battery on or off with five rapid clicks of the button. Change heat settings from low (white) to medium (blue) to high (red) with three rapid clicks. Engage "preheat" mode with two rapid clicks.