Storage Space

• The first-generation iPod Nano comes in 1-, 2- and 4 GB versions. The second-generation versions are available in 2-, 4- and 8 GB sizes. Both versions use flash drive memory, which differs from the memory in other types of iPods.
  
  

Colors

• The first-generation iPod Nano is available only in black and white. The 2 GB second-generation iPod Nanos are available only in silver. The 4 GB versions are available in silver, green, blue, pink and red; 8 GB versions are available in black and red.
  
  

Battery Life

• Both versions have an internal rechargeable lithium ion battery. The first-generation iPod Nano had an average battery life of 14 hours of audio playback. The second generation's battery life was improved to an average of 24 hours of music playback.