The Apple iPod touch 2nd Generation effectively is to the iPhone 3G what the original iPod touch was to the original iPhone -- offering much of the same iPod and handheld computing functionality but lacking the "phone", mobile phone networking (3G/EDGE), A-GPS, and integrated camera.

The iPod touch 2nd Generation features a "thin contoured metal design" reminiscent of the iPhone 3G shape that is slightly thicker (0.02 inch) but lighter than the original iPod touch with a silver front trim rather than gray. Like the original model, the iPod touch 2nd Generation features a "multi-touch" sensitive 3.5" display with 320x480 resolution -- albeit a higher-quality one than that provided by the original -- an accelerometer that allows the device to "know" whether it is being held in portrait or landscape mode and switch automatically, an ambient light sensor to adjust screen brightness, built-in support for Wi-Fi (802.11b/g), and 8, 16, or 32 GB of flash memory.

Compared to the original iPod touch, the second generation model has welcomed external volume controls on the left side of the device, an integrated speaker (external microphone supported via the Apple Earphones with Remote and Mic), built-in support for the Nike + iPod Sport Kit, a "Genius" feature to dynamically create playlists based on "songs that go great together", and shaking the device gently "shuffles" songs.

Battery life is improved as well, as the 2nd Generation model provides 36 hours of music playback and 6 hours of video, compared to 22 hours of music playback and 5 hours of video playback for its predecessor.
https://everymac.com/systems/apple/ipod/specs/ipod-touch-2g-specs.html