As iPad Mini launch looms, Amazon says $199 Kindle Fire HD is the biggest-selling product on its site

Of all of Amazon's tablet and e-reader products, the $199 7-inch Kindle Fire HD is the most popular, the e-commerce giant announced on Monday. The news came the day before Apple is expected to enter the mini-tablet market with the launch of a smaller version of its popular iPad device.

The day before tech titan Apple is expected to unveil a smaller version of its iPad tablet, Amazon has piped up to remind everyone that it also has some mini-sized tablets on the market, with the announcement that its $199 Kindle Fire HD device has become the biggest-selling product on its website worldwide. That’s not bad going for a product which – outside of the US – is only currently available in five countries: France, Germany, Italy, Spain and the UK. Even then, in these locations it can only be pre-ordered, with its release date listed as October 25.

Of course, it would be wonderful to know exactly how many of the 7-inch tablets have been snapped up (or pre-ordered) by consumers since its launch in September, but true to form, the company hasn’t released specific sales figures. Instead we’ll have to make do with what a spokeswoman for the e-commerce giant told Reuters – that its best-seller status is based on unit sales, as opposed to revenue or some convoluted percentage-based calculation.

That puts it ahead of the cheaper $159 Fire and pricier 8.9-inch Kindle Fire HD devices. It also means it’s selling in greater numbers than its family of Kindle e-readers, including the recently launched Paperwhite device. Incidentally, it was reported earlier on Monday that Amazon has quietly retired its Touch e-reader, with a message on the Touch’s old landing page directing consumers to the Kindle Paperwhite, described on the page as “a newer model” of the Touch.

But how will Amazon’s tablets shape up against Apple’s expected iPad Mini, a device likely to sport more features, but also a heftier price tag? Or are they targeting two entirely different sets of consumers?

Either way, all eyes are now on the California Theater in San Jose where on Tuesday Apple will (almost certainly) pull the covers off a smaller iPad, entering the mini-tablet market for the first time – a space currently dominated by the likes of Google with its Nexus 7 device and Amazon with its Fire tablets.