I have a bunch, it was cheaper to get a pack that has car charger, another wall charger and a usb cable than just one of those. I have no idea which one I wanted, it was $6, whereas it was like $8 for just whatever I wanted.
Also, my kindle's usb thing is the same size so it works. And I've since somehow wound up with like three other usb cables that fit.
I guess what I'm saying is I don't know where usb cables come from? When a daddy and mommy usb cable love each other very much?