Specification :
When creating i - Phone 4, Apple designers and engineers didn’ t start with a clean sheet of paper. They started with three years of experience designing and building the phones that redefined what a phone can do. i - Phone 4 is the result of everything they’ ve learned so far. And it’ s all contained in a beautiful enclosure a mere 9.3 millimeters thin, making i - Phone 4 the world’ s thinnest smartphone. With its easy-to-use interface, amazing features, and rock-solid stability, i - OS — Apple’ s mobile operating system — is the foundation of i - And even as other phones try to catch up, the technologies and features built into i - OS 4 keep it years ahead of the competition. - Tunes Store) , HE-AAC, MP3 ( 8 to 320 Kbps) , MP3 VBR, Audible ( formats 2, 3, 4, Audible Enhanced Audio, AAX, and AAX+ ) , Apple Lossless, AIFF, and WAV User-configurable maximum volume limit Message: SMS, MMS.