Table:
text: Comparison of e-book readers
Electronic-paper displays
Electronic-paper displays
Maker Model Intro_year Screen_size_inch Self_lit Screen_type Weight Screen_pixels Touch_screen micro_SDHC
Aluratek Libre Ebook Reader Pro 2009 5 no ePaper 213g (7.5oz) 600 × 800 No up to 32 GB
Amazon.com Kindle Paperwhite 3G 2012 6 Yes eInk Pearl 221g (7.8oz) 758 × 1024 Yes 2-Point No
Amazon.com Kindle Paperwhite Wi-Fi 2012 6 Yes eInk Pearl 213g (7.5oz) 758 × 1024 Yes 2-Point No
Amazon.com Kindle (4th generation) 2011 6 no eInk Pearl 170g (6.0oz) 600 × 800 No No
Barnes & Noble Nook Simple Touch 2011 6 no eInk Pearl 212g (7.5oz) 600 × 800 Yes Yes

Question: Looking at the comparison of e-book readers, how many screen pixels does Amazon.com's device weigh 221 g (7.8 ounces) for electronic paper?