This adapter worked perfectly for my dual-voltage cell phone and camera battery chargers. Because both of those can use the 220 current, this plug adapter was all I needed to charge them up in my hotel rooms. I was traveling light, so I was glad that this adapter is small and compact, and that it could charge TWO devices at the same time. I could plug one device into the electrical outlet portion of this adapter (using my standard U.S. plug) and I could plug the other devices into the USB slot on the bottom of this adapter. IMPORTANT - it has only ONE input for a U.S. electric plug and only ONE slot for a single USB. Also, be aware that it is NOT a surge protector and it is NOT an electric current converter. Your U.S. devices must be dual-voltage capable to be charged up using only this adapter.