I’ve had many of these in the past. I use it regularly, sometimes just for a top up and other times for a complete charge. It is small and light, about the same sort of bulk as an old style cigarette lighter. The charging time is comparable to using a USB port on a laptop or computer. My son is at university and I got him one as a present several weeks ago; he says it is invaluable as he had to rely on an in car charger & now he can take this device on campus without the stress of repeatedly checking the remaining battery life on his phone!