The latest model iPod Nano is available in black, grey, purple, pink, yellow and green.
The iPod Nano 6th generation can be identified by its square shape and touch screen.
The 5th generation Nano can be easily identified by a video camera eye located on the reverse. The model number begins with MC.
The 4th generation Nano can be identified by its rectangular shape. It does not have a built-in video camera and the model number begins with MB.
The 3rd generation Nano can be identified by its almost square shape.