In the two years since the introduction of the Kindle, Amazon has improved the design infinitely with the likes of its Paperwhite and Fire range. Now the mega-retailer has unveiled the latest evolution of its flagship tablet with the Kindle Fire HDX. Starting at $229 USD for the 7″ version and $379 USD for 8.9″, the Kindle Fire HDX boasts a new graphics engine, double the memory of the Kindle Fire HD, and triple the processing power. Housed within the magnesium unibody/molded glass-nylon alloy redesign is a 2.2 GHz quad-core processor – capable of 339 ppi, perfect 100% sRGB color accuracy, improved brightness and dynamic image contrast – a battery that lasts 17 hours when reading, and a bevy of application updates including the ability to download Prime Instant Videos for watching offline. The HDX also introduces the “Mayday” button, thus allowing users to contact an Amazon expert of the fly – who can then guide the user by drawing on the screen and providing a walkthrough with step-by-step instructions – should they ever run into any issues. Amazon’s Kindle Fire HDX tablets are now available to pre-order and are due out beginning October 18.