Amazon is refreshing its lineup of tablet computers with a new Kindle Fire HDX. They say it's faster and lighter than previous Kindles and it comes in two versions, a 7-inch and an 8.9 inch. 
According to Amazon, both have more pixels per inch than Apple's iPad. And there's a new feature called "Mayday" that lets users summon a live customer service rep right on the screen. 
Earlier this year Amazon Kindle had 17 percent of the US tablet market compared with Apple's iPad at 48 percent. The new Kindles are available for pre-order today.
--Rob Archer