USB Charger for Mazda CX-5

Hi guys,

I just picked up a 2014 Mazda CX-5. There is only 1 USB port in the car that gives a really terrible iPhone charge (my understanding is that the USB port is for connecting up audio, not for charging).

Is anyone able to recommend a USB car charger that will fit the Mazda's oddly shaped 12V socket? Brands like Tronsmart explicitly state that their products don't fit Mazdas, so if you're a Mazda owner who has gotten extra USB ports into their car for the purpose of charging devices, please let me know what brand you bought.

Many thanks.