The iPod Shuffle (stylized and marketed as iPod shuffle) is a discontinued digital audio player designed and formerly marketed by Apple Inc. It was the smallest model in Apple's iPod family, and was the first iPod to use flash memory. The first model was announced at the Macworld Conference & Expo on January 11, 2005; the fourth- and final-generation models were introduced on September 1, 2010. The iPod Shuffle was discontinued by Apple on July 27, 2017. Overview 1st generation Released on January 11, 2005 during the Macworld expo, the first-generation iPod Shuffle weighed , resembled a pack of chewing gum sticks, and was designed to be easily loaded with a selection of songs and to play them in sequential or 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 used the SigmaTel STMP35xx system on a chip (SOC) and its software development kit (SDK) v2.6, a flash memory IC, and USB rechargeable lithium cell. The STMP35xx SOC and its software was the most fully integrated portable MP3 playback system at release time and SigmaTel was Austin's largest IPO (2003) capturing over 60% of flash based MP3 player world market share in 2004. In 2005, peak iPod first-generation Shuffle production occurred at a hundred thousand units per day, at the Asus factory. It lacks a display, the trademark click wheel, playlist management features, and the games, address book, calendar, alarm, and notes capability of larger iPods. Due to the codec not being ported, it is incapable of playing Apple Lossless and AIFF audio files. The iPod Shuffle series also lacks a real-time clock and does not therefore update the "Last Played" value in iTunes. The 1 GB model was advertised as capable of holding up to 240 songs (based on Apple's estimate of four minutes per song and 128 kbit/s AAC encoding). To cater to the limited capacity and intended usage scenario, two new features were added to iTunes: AutoFill, which selects songs at random from a user's music library (or from a specific playlist) and copies as many as would fit into the iPod Shuffle's storage - available as a supplement or replacement to manual selection; and an option to automatically transcode audio files of higher specifications to 128 kbps AAC-LC while transferring