I purchased the Power Bank because the battery life of the AirVape Xs is very short. [Too short and very disappointing to me, but it is my first vaporizer, so I don't have anything to compare it to. Pre-purchase research indicated that the battery life is pretty good for a vaporizer.] The Power Bank is very slim and light-weight. Only minor issue is it did not come with any instructions, so I wasn't sure what the blue indicator light meant while charging. In short, the less it blinks, the lower the charge, and it is fully charged when the light is solid. (e.g., when you first plug it in, it will blink once or twice, and increase the blinking to 4 or 5 times as the charge increases. The light turns solid blue when fully charged.)