First generation

The iPod shuffle is designed to be easily loaded with a selection of songs and to play them in random order. According to Apple, owners of existing iPods had often left the music selection to "shuffle", and the new iPod shuffle was a way of implementing that in a much more cost-effective fashion. It relies on the use of an "autofill" feature in iTunes, which can select songs at random from a user's music library (or from a specific playlist) and copy as many as will fit into iPod shuffle's memory. It can hold up to 240 songs (1 GB model, based on Apple's estimate, of four minutes per song and 128 kbit/s AAC encoding).

It lacks the trademark display, scroll wheel, playlist management features, games, address book, calendar, and notes capability of earlier iPods, and cannot be used with iSync. In addition, it is incapable of playing Apple Lossless and AIFF audio files, unlike other iPod models due to its lower processing power. The iPod shuffle has a better bass sound quality than its larger iPod kin, according to one review.^[3] The first generation shuffle weighed only 0.73 ounces (approximately 20 grams).

First generation iPod shuffle with the cap removed to show the USB connector. The cap snaps onto the unit. iPod shuffle comes with a second cap on a lanyard which a user can wear around his or her neck.

iTunes offers some new features for iPod shuffle. One is the ability to reduce the bit rate of songs to 128 kbit/s AAC. The conversion is done automatically, with the original file left untouched on the computer and the smaller (lower bit rate) file sent to the iPod shuffle. Older versions of iTunes allowed an iPod shuffle playlist to be viewed and changed while the unit is not connected; the next time the unit is connected, it can then be updated with the changed playlist. This functionality is no longer a part of iTunes as of iTunes 7.

The front of the iPod shuffle has buttons for Play/Pause, Next Song/Fast Forward, Previous Song/Fast Reverse, and up and down volume adjustment. On the reverse, it has a battery level indicator light (activated by a button) and a three-position switch to turn the unit off or set it to play music in order or shuffled. It plugs directly into a computer's USB port (either 1.1 or 2.0), through which it also recharges its battery, which has an expected life of around 12 hours between charges. The USB plug is hidden beneath a cap. The unit also comes with a lanyard that attaches to the iPod shuffle via an attached cap and this allows the user to wear the iPod shuffle around his or her neck.

iPod shuffle can also be used as a USB flash drive. iTunes allows a user to set how much of the drive will be allowed for storing files, and how much will be used for storing music.

First generation iPod Shuffles were originally sold at US$99 for 512 MB (0.5 GB) models, and US$149 for 1 GB models. In February 2006, the prices for first generation iPod shuffles were lowered to US$69 and US$99 respectively.

Second generation

A Second-generation iPod shuffle in size-comparison to a Dell mouse.

On September 12, 2006 Apple announced the release of the second generation iPod shuffle, calling it "the most wearable iPod ever".^[4] First shipments of the unit were slated for an October 2006 arrival, but actually started shipping on Friday, November 3, 2006^[5]. The new generation featured a lone 1 GB model at US$79, GB£49, CA$89, AU$119 or €89 (France) in a silver brushed aluminum case similar to the second generation iPod nano and the older iPod mini. The new model is less than half the size of the first generation model at 41.2 x 27.3 x 10.5 mm (1.62 x 1.07 x 0.41 in), and is reminiscent of the iPod radio remote available for iPod nanos and 5th generation iPods. Apple branded it as the "world's smallest MP3 player". This size includes the new built-in belt clip; the actual unit itself is thinner, with the entire device weighing only 15.5 g (0.55 ounces). The power and shuffle/no shuffle switches were also separated into two controls to prevent accidental choice of shuffle when that may not be the desired mode of operation. The formatting of the iPod itself is new to Apple, as the 2G (2nd Generation) Shuffle will only format itself to FAT32. iTunes issues a warning that the iPod is incorrectly formatted if brought to the Macintosh format HFS+. All previous iPod models have allowed the usage of either the Mac format or the PC format.^{[citation needed]}

Orange second generation iPod shuffle

On the second generation iPod shuffle, USB connectivity is provided via an included dock, which transfers data through the headphone jack. The second generation iPod shuffle is also able to act as a flash drive, just like the first generation iPod Shuffle. However, unlike the first generation iPod shuffle, the second generation does not have a built-in USB connector. This means the dock is required for connection to a computer on the second generation model.

The second generation Shuffle can play MP3, MP3 VBR, AAC, Protected AAC,, Audible (formats 2, 3 and 4), WAV and AIFF, meaning that the only iTunes format not supported is Apple Lossless. (Note that using WAV or AIFF on a 1GB device will mean very few songs may be held.)

On January 30, 2007 Apple announced the addition of four new colors to the iPod shuffle line. In addition to the original silver, a pink, orange, green and blue color has been made available via the Apple Store (online). Of the colours the blue, green, and pink are essentially the same hues as the second generation minis and nanos. The new orange color is a first for the iPod franchise. They also now come with the new redesigned headphones that were not included with the original silver model. The box was also changed to have gray text instead of the lime-green text, lime-green showing that the original headphones are included, and gray text showing that the new headphones are included.