the USB ports are only rated 0.5 amp, - the picture shows 1000maA - which isn't enough to run and charge my satnav. Fortunately the cigarette charger sockets are more powerful and the original satnav adapter works in those, but it isn't what I really wanted.
I have used both the usb and the cigarette lighter sockets and it has worked perfectly. Just wish I had purchased one sooner to keep all of mine and my partners devices charged on the long trips! Fantastic price and buy.
Not much to say really other than this works perfect. The only issue I have is finding a spot for it in my car but thats another issue. Both USBs work fine and allow both my girlfriend and me to charge our phones and have the MP3 player charging/playing when on long journeys. The cable is long enough to reach from the cigarette lighter (which sits at the bottom of my console) to the top of the dashboard or in my case the shelf above the glovebox. Well worth the £4.00
These have been perfect as I need cigarette lighter for my FM transmitter and can usb charge my phone at the same time.
The cable provides flexibility so I can place it conveniently behind the ashtray and though cheap it lasted a full two years before giving up on me. Have ordered another one of exactly the same as it's perfect.