I bought this as my wife and I have a variety of devices (MP3 players, phones etc) that can be charged via a USB connection. With this I can have these devices charging off the car battery, and I can have both a phone and an MP3 player charging at the same time, very handy for long journeys.
The device has a cigarette lighter plug at one end, is hinged in the middle and then 2 USB ports at the other end. There is an LED to indicate that it is working. The hinge locks into 6 different positions, to allow you to easily arrange leads, plug and devices neatly. Both USB ports work at the same time. There is a sturdy well built feel to the device, and so far it has worked perfectly for me. With one exception – it will not charge my wife’s Blackberry Curve. It works just fine on my Sansa Clip+ MP3 player, and on my Nokia phone. 4 stars. Would have been 5, but it seems that it is not quite totally universal.