The LoKey 350mAh Key Box Battery encapsulates all of the best qualities of a travel friendly device. It’s sleek and inconspicuous design quality of being a key fob make it a trouble-free addition to any key chain. A single side button flips up the point of attachment which has a similar movement to a switch blade. With 510 threading, this piece easily fits a vast variety of cartridges or tanks on the market. The LoKey releases 350mAh of power to ultimately reach 3.7V of output. With that peak of power, this device is most ideal for use with e-liquids or oils.