Amazon error reveals Microsoft's rival to Apple's iPad mini When it comes to the latest tablet device in Microsoft's arsenal, however, Amazon has let the cat out of the bag. The online retailer has accidentally published pictures of a new 7-inch Acer tablet, which would break new ground as the first small tablet to run on Microsoft's Windows 8 operating system. It is thought to be one of a number of tablets which Microsoft will use to compete with Apple's iPad Mini, Google's Nexus 7 and Amazon's own Kindle Fire device, in the tablet-makers' intensifying battle for dominance. According to the listing, which appeared briefly on Amazon's US website before being removed, the Acer Iconia W3 will be priced at $379.99 (£244) for a 32GB model. There were no details about when the device might be launched, but it is expected to be in the next few months. The company founded by Bill Gates made its tablet debut last year, with the launch of its Surface, which includes a detachable keyboard. Sales of the device have disappointed analysts, but Microsoft has argued that it always intended the first Surface as a flagship product to establish a foothold in the tablet market, and that bigger sellers would follow. The company is expected to detail plans for two more, smaller, versions of the Surface at a developers' conference next month, including another 7-inch device which will sit alongside the Acer Iconia. Microsoft is among old-guard technology behemoths under pressure to take a slice of the lucrative tablet market, as sales of PCs fell 14pc last year.