BeBook One. Diagonal: 152.4 mm (6 "), Gray scale levels: 16 levels of grey, Display resolution: 600 x 800 pixels. Document formats supported: djvu, epub, pdf, rtf, Audio formats supported: mp3, Image formats supported: bmp, gif, jpg, png, tif. Internal storage capacity: 0.5 GB, Compatible memory cards: SD, Maximum memory card size: 4 GB. Interface type: USB 2.0. Battery technology: Lithium-Ion (Li-Ion), Battery capacity: 950 mAh, Battery voltage: 3.7 V