The iPod Nano Fourth Generation main features are:

• Dimensions: 3.6” x  1.5” x 0.24” (90.7 mm x  38.7 mm x 6.2 mm)
• Weight: 1.3 ounces (36.8 grams)
• 2” (diagonal) LCD with blue-white LED backlight
• 8 GB or 16 GB flash drive memory
• Holds up to 2,000 or 4,000 songs in 128-Kbps AAC format
• Holds up to 7,000 or 14,000 iPod-viewable photos
• Holds up to 8 hours or 16 hours of video
• Frequency response: 20Hz to 20,000Hz
• Impedance: 32 ohms
• Audio support: AAC (16 to 320 Kbps), Protected AAC (from iTunes Store), MP3 (16 to 320 Kbps), MP3 VBR, Audible (formats 2, 3, and 4), Apple Lossless, AIFF, and WAV
• Photo, support: JPEG, BMP, GIF, TIFF, PSD (Mac only) and PNG formats Video
• Video support: m4v, .mp4, and .mov file formats
• Built-in rechargeable lithium ion battery, with up to 24 hours of music playback time or up to 4 hours of video playback time when fully charged
• Colors: Silver, black,  purple, blue, green, yellow, orange, red and pink
• More information: http://www.apple.com/ipodnano/
• Suggested price in the US: USD 149 (8 GB); USD 199 (16 GB)