iPod PP5020 2004

The Apple iPod (Fourth Generation) featured a 20 GB or 40 GB 4200 RPM ATA-66 hard drive, capable of holding "up to" 5,000 or 10,000 songs in "128-Kbps AAC format" and offered 25 minutes of skip protection. The iPod (4G) was similar to the third-generation models but had a slightly thinner enclosure and an improved display. It adopted the revolutionary "ClickWheel" from the iPod mini and significantly extended battery life to "up to" 12 hours of continuous music playback.

In addition to the improved battery life, updated software moved the "Shuffle Songs" feature to the main menu and retained the voice record feature, games, and alarm clock from the third-generation models.

The 40 GB model included a "dock" for quick and easy computer connection, which could be purchased separately for the 20 GB model at an additional cost.

The fourth-generation iPod is overwhelmingly remembered for one key innovation: the Click Wheel. Adopted from the wildly successful iPod mini, this feature integrated the buttons directly into the touch-sensitive scroll wheel, creating what many considered the definitive iPod interface. It was universally acclaimed for its elegant simplicity and superior one-handed usability, resolving the ergonomic debates sparked by the previous generation. This model was also praised for its improved battery life, which was a significant enhancement for users. While the overall design was an evolution of the third generation, the adoption of the Click Wheel was seen as a perfecting of the formula. It made navigating thousands of songs faster and more intuitive than ever, solidifying the iPod's reputation as the gold standard in portable music players.