Single or double din?

[Magicmart]

Hay silly question most prob but how do I know if I have a Single or double din? As I'm thinking of up grading to a sat nav I have a 58 a3 with an audi concert radio

 

[A3Kent]

Google

 

[mjr901]

double din

 

[_G_]

+1

 

[c_w]

Double din is standard I believe from 2007 on. I have the concert, it's handy that is plays MP3 but it is the WORST control system I have ever used. It is so needlessly complicated to change folders on a CD it is so bad it's funny, buttons change function depending on status (unforgivable considering the amount of buttons available), and the way folders are shown is not clear at all. I have a Becker MP3 player in my other car and with one rotary knob can control file selection, it's so intuitive, such as shame the AUDI headunit is so bad for this.