Griffin Powerjolt Dual USB Micro Car Charger - Non Retail Packaging
I tried to use this in my 2 cars in the various cigarette-lighter sockets.  It worked in some of them, not at all in others.  Once I got stuck trying to figure out which exit to take for an important meeting and my GPS shut down,  since this plug did not provide power.  After trying it in all the various sockets, I realized the spring-loaded center-contact was NOT reaching  the socket center contact and was not providing power. In my Chevy Prizm it did reach the contact, but in my Nissan Maxima it did not. 