The iRiver Clix (stylised iriver clix) is a portable media player that was developed and sold by iriver through two generations. The Clix was originally known as the U10, released in 2005. The next year it was revised and essentially rebranded to Clix. A second generation player, often called the Clix 2, was released in 2007, and later a minor revision called Clix+. The players are navigated by four buttons embedded on its sides, referred to as D-Click. U10 iRiver introduced the U10 in June 2005. It was available in capacities of 512MB and 1GB. The player has a 2.2-inch (55 mm) 18-bit (262,144 colors) QVGA (320 x 240) TFT LCD screen covering most of its faceplate. It sits above the buttons, called the D-Click System. It allows the device to be used in a touch sensitive fashion despite it not being touch sensitive. There are also minimal-sized buttons on the sides for power, button lock, volume, and a Pivot key that instantly changes the screen orientation. The U10 supports audio formats of MP3, WMA (including protected WMA), and Ogg Vorbis. As with some previous iRiver players it includes SRS WOW 3D sound technology. Additionally it also plays content in the MPEG-4 SP video format (other formats are converted with included software), the Unicode text format, and Flash Lite games and animation. There is also a built-in FM tuner and recorder, a microphone and an alarm clock. An optional docking cradle was also sold for the U10, alongside a remote control. The cradle has stereo speakers, an additional line in input, and a snooze button on the top so that it can be used like an alarm clock. Clix In May 2006, the Iriver Clix was introduced. While physically identical to the U10, the Clix had an overhauled user interface with improved performance. It was provided initially in 1 GB and 2 GB capacities and retailed for a lower price than the U10 did. In November 2006, a 4 GB version was released, retailing for $200 in the United States. The Pivot key was also replaced by the "Smart Key" which is a customisable button that can be assigned by the user to various functions. iRiver also worked with Microsoft and MTV, offering immediate compatibility with Windows Media Player 11 (then in beta) and MTV's Urge online music service. The Clix is also PlaysForSure certified. Clix 2 iRiver previewed several