Energy Sistem 345878. Diagonal: 152.4 mm (6 "), Technology: E-Ink Vizplex, OSD, Gray scale levels: 4 levels of grey. Document formats supported: pdf, epub, Audio formats supported: MP3, WMA, AAC, WAV, FLAC, APE, Image formats supported: JPG, BMP. Internal storage capacity: 2 GB, Compatible memory cards: SD, SDHC, Maximum memory card size: 16 GB. Interface type: USB 2.0. Battery technology: Lithium-Ion (Li-Ion), Battery capacity: 1200 mAh, Battery voltage: 3.7 V