Sony PRST2HBC. Diagonal: 152.4 mm (6 "), Technology: E Ink Pearl, Gray scale levels: 16 levels of grey. Document formats supported: ePub, PDF, Image formats supported: BMP, GIF, JPEG XR, PNG. Internal storage capacity: 1.3 GB, Compatible memory cards: microSD (TransFlash), Maximum memory card size: 32 GB. Interface type: USB 2.0. Battery voltage: 3.7 V, Battery recharge time: 2.5 h