20 GB model holds up to 5,000 songs; supports AAC (16 to 320 Kbps), MP3 (32 to 320 Kbps), MP3 VBR, Audible, AIFF, Apple Lossless and WAV

Up to 12 hours battery life when fully charged (typically 4 hours); fast-charge in as little as 2 hours
Mac OS X or Windows 2000 and XP compatible; FireWire and USB 2.0 interface for fastest digital transfer available
Feature upgrades from previous version include new Click Wheel, slimmer case, and easier navigation
Comes with earbud headphones, AC adapter, FireWire cable, and USB 2.0 cable (dock not included)