Amazon Kindle Paperwhite 3G. Diagonal: 152.4 mm (6 "), Gray scale levels: 16 levels of grey. Document formats supported: DOC, DOCX, HTML, MOBI, PDF, PRC, TXT, Image formats supported: BMP, GIF, JPG, PNG. Internal storage capacity: 2 GB, Maximum memory card size: 0 GB. Interface type: USB 2.0, Wireless LAN type: 802.11b, 802.11g, 802.11n, Data network: 3G, EDGE, GPRS, HSDPA. Battery life (max): 1440 h, Continuous reading time: 15 h, Battery recharge time: 4 h