iPod is a brand of portable media players. All iPods can function as mass storage devices to store data files. Connect the audio output from any 3.5mm source to the Stereo input on your component stereo or Amplified Speaker system. Devices in the iPod range are primarily digital audio players, designed around a central click wheel with exception to the iPod Shuffle, which uses buttons because of its size. This 3.5mm Stereo Plugs expands from 4" to 48". The full-sized model stores media on an internal hard drive, while the smaller iPod nano and iPod shuffle use flash memory. Like many digital music players, iPods can also serve as external data storage iPod can play MP3, AAC/M4A, Protected AAC, AIFF, WAV, Audible audiobook. iPod photo introduced the ability to display JPEG, BMP, GIF, TIFF, and PNG image file formats. iPod's operating system is stored on its dedicated storage medium. The battery could also be charged with a power adapter that was included with the first four generations. The third generation began including a dock connector, also brought opportunities to exchange data, sound and power with an iPod. the iPod's 30-pin Dock Connector allows iPods to be connected to a variety of accessories, which can range from televisions to speaker systems.