CPU
CPU: ARM7TDMI
CPU Speed: dual 80 MHz embedded
Data Path: 32 bit
ROM: 32 MB
Onboard RAM: 32 MB
RAM slots: 0
Maximum RAM: 32 MB

Video
Screen: backlit LCD
Max Resolution: 1-bit 160x128

Storage
Hard Drive: 20/40 GB 4200 RPM
ATA Bus: ATA-66

Input/Output
USB: via Dock Connector
Firewire: via Dock Connector
Audio Out: stereo 16 bit mini
Speaker: clicker

Miscellaneous
Codename: ?
Dimensions: 4.1" H x 2.4" W x 0.57" D
Weight: 0.35 lbs.
Minimum OS: iPod OS 3.0
Maximum OS: iPod OS 3.1
Introduced: July 2004
Terminated: June 2005

Notes

the 40 GB model was 0.69" deep and weighed 0.39 lbs.

Announced in July 2004, the iPod (Click Wheel) was thinner, lighter, and cheaper than its predecessor. It also featured a redesigned hardware interface, based on the successful Click Wheel interface used for the iPod mini. Battery life was also dramatically improved, thanks to the use of a PortalPlayer PP5020 System-on-a-chip, which was much less power-hungry than the PP5002 used in previous players. The iPod (Click Wheel) was available in two models: a 20 GB model sold for $299, while a 40 GB model was available for $399. In February 2005, the 40 GB model was dropped, and the price of the 20 GB model was cut to $249.

Picture Credits:
Apple Computer, Inc.