Irradio BOOST B 4GB. Player media type: Flash, Total storage capacity: 4 GB, Compatible memory cards: microSD. Audio formats supported: MP3, WMA. Impedance: 32 Ом, MP3 bit rates: 8 - 320 Kbit/s, WMA bit rates: 32 - 384 Kbit/s. Interface: USB 2.0. Speaker power: 0.5 W