The Scosche USB12V2. It has two 1A (1000mA) USB ports. Most car chargers are 500-600mA which means the phone is barely charging if you are using it for GPS, etc. Since it has standard USB ports, you can charge a plethora of devices.
$9.56 shipped from Amazon if you have Amazon Prime, otherwise you have to pay a few bucks for shipping.
$9.56 shipped from Amazon if you have Amazon Prime, otherwise you have to pay a few bucks for shipping.