Best FM Modulator?

The Miata I bought doesn't have an AUX input. My son wants to rock out to his music but I need my phone to talk to the car. Can anyone recommend a FM modulator?

thanks

Have you tried plugging that rando 1/8 jack into a sound source? IIRC they should have an aux port, pretty close to where your mystery box is. 

I have a tranzit blu that hardwires into the antenna cable. Excellent sound and better than the blutooth ones I tried. 

@keith, there is nothing behind the mystery box. I took it out and it looks like their used to be some buttons/switches there but they are missing. 

I have this one in my Escalade and it works flawlessly.

My wife has this one in her 9-3SC and it seems fine as well, though not as fancy.

Both are used for streaming and calls in relatively quiet vehicles.