Amazon Kindle 4. Diagonal: 152.4 mm (6 "), Technology: E Ink, Display resolution: 600 x 800 pixels. Document formats supported: DOC, DOCX, HTML, MOBI, PDF, PRC, TXT, Image formats supported: BMP, GIF, JPG, PNG. Internal storage capacity: 2 GB. Interface type: USB 2.0, USB connector type: micro USB B, Wireless LAN type: 802.11b, 802.11g, 802.11n. Colour of product: Grey