This charger is very compact and lightweight. I have have used it to charge 3 different ways directly in the USB port of my extension cord, connected to an adapter, and connected to my computer. The slowest charge I received was connected to computer but that does not surprise as that generally is a slow way to charge my devices, in this case it's my phone. And the fastest was using my adapter. It took less than an hour to charge with my adapter. I'm not sure if that is typical but anytime I charge with this particular adapter I get a really fast charge. It does not matter what cord or charger I use.