On September 9, 2008, Apple introduced the fourth version of its iPod nano, a thin iPod featuring a sleek design with a curved aluminum and glass enclosure. The new iPod nano comes with a technology that creates playlists from songs in your music library. The new iPod nano also features a refined user interface, a high resolution portrait display and a built-in accelerometer which automatically switches to cover flow when rotated and automatically goes into shuffle mode when lightly shaken. The new iPod nano gives users up to 24 hours of music playback or four hours of video playback. Both models come in silver, purple, blue, green, orange, yellow, pink, red and black. With up to 24 hours of music playback or four hours of video playback on a single charge, the new iPod nano is the ultra-portable way to enjoy music, TV shows, movies, and games on the go. The 8 Gig model holds up to two thousand songs, seven thousand photos and eight hours of video. The 16 Gig model holds twice as much. The new iPod nano costs $149 for the 8GB model and $199 for the 16GB model.