Amazon has today unveiled its new third-generation tablet called the Kindle Fire HDX. Like its predecessors, the device is available in 7-inch and 8.9-inch variants, and both feature speedy quad-core Snapdragon 800 processors, high-resolution displays, 2GB of RAM, and stereo speakers.

The larger model also offers an 8-megapixel rear-facing camera, which is a first for the Kindle Fire lineup.

In addition to the new models, Amazon has refreshed the Kindle Fire HD to add improved displays, faster processors, and Amazon’s latest software. The retail giant has also reduced the price of the 7-inch device to $139, while the 8.9-inch model is now just $269.

The new Kindle Fire HDX is a big improvement over its predecessor, and it gives the Kindle Fire family a better chance of competing with other affordable slates like the Google Nexus 7. Starting at $229, the 7-inch model offers a 1920×1200 display with 323 pixels-per-inch, as well as up to 11 hours of battery life during “mixed use,” and up to 17 hours of battery life while reading.

The 8.9-inch model, which costs $379, has an even sharper 2560×1600 display with 339 pixels-per-inch, which makes the Retina iPad’s 264 pixels-per-inch look pretty disappointing. It also offers 12 hours of battery life during “mixed use,” 18 hours of battery life while reading, and an 8-megapixel rear-facing camera.

Both Kindle Fire HDX variants pack 2.2GHz quad-core Snapdragon 800 processors, 2GB of RAM, dual stereo speakers, front-facing HD cameras, and 16GB, 32GB, or 64GB of internal storage. 4G LTE connectivity is also an optional extra for both models, and both ship with Amazon’s latest Fire OS 3.0 operating system, which comes with features like X-Ray for Music, and Prime Instant Video.

Amazon is also introducing a new feature with these devices called “Mayday button,” which “delivers revolutionary live tech support—one touch connects you to an Amazon expert who can guide you remotely through any feature—24×7, 365 days a year.”

As for the Kindle Fire HD, that now starts at just $139 for the 7-inch model, which offers a 1280×800 display with 216 pixels-per-inch, a 1.5GHz dual-core processor, stereo speakers, and 8GB or 16GB of internal storage.

The 8.9-inch Kindle Fire HD is now priced at $269 and offers a 1920×1200 display with 254 pixels-per-inch, the same 1.5GHz processor, a front-facing camera, and up to 64GB of storage with the 4G model.

The refreshed Kindle HD also comes with Fire OS 3.0 pre-installed.

Amazon’s new tablets are available to pre-order today from Amazon.com; the 7-inch Kindle Fire HDX will begin shipping on October 18, while the 8.9-inch model will begin shipping on November 7. The new Kindle Fire HDs will ship on October 2.

• SourceAmazon