As you can see from the image above the Trekstor Pyrus Mini is a close cousin of Trekstor's 6" Pyrus ereader. It ships with 2GB Flash storage, a microSD card slot, and optional Wifi. There's no touchscreen. Primary format support includes Epub and PDF, and this ereader also supports some image formats.
I haven't found complete specs on this but the weight is reportedly 111 grams, making this the lightest ereader on the market when it ships. Retail will be 50 euros and this ereader should be available in German retail stores in November.
Assuming the resolution claim pans out, this ereader will have a resolution of over 232 ppi. That's an impressive increase in sharpness over the screen on Kindle Paperwhite, which can only boast a resolution of 212 ppi. Of course this new E-ink screen still falls short of many other smartphones but it is still a step up for E-ink.
If anyone wants to see it in person, Trekstor will be showing it off at the Frankfurt Book Fair next month.
Until Trekstor announced the Pyrus Mini, ereader makers only had the option of 5" or larger E-ink screens, with the first of the 5" E-ink showing up in 2009. I saw a couple at CES 2010 in the Hanvon booth, one of which I later bought (it's still in a drawer somewhere). This is a much better size, IMO. This device is going to be much easier for you to stick in some pockets, and it will be easier to grip both edges in a single hand.
This new ereader also confirms E-ink's interest in getting their screen tech on smartphones. Perfecting the design of the new 4.3" screen wasn't cheap, and Trekstor probably could not have funded it on their own. No offense, but they just won't sell enough Pyrus Mini to justify the expense.
No, this screen was likely financed by the maker of a smartphone. That's the only consumer industry that I know of which would be interested in this screen size and have the funds to cover the costs. And it wouldn't be the first E-ink screen used on a smartphone; that privilege belongs to the Alias 2 phone from Samsung.
This double hinged phone debuted in 2009 with a secondary E-ink screen in place of the keys. That was a custom design which allowed the keys on the phone to rotate in orientation, a feature which is worth copying on whichever device uses the new 4.3" screen.
Of course, that new screen could also have been financed by Amazon but I doubt they are planning to use this 4.3" screen. If that were the case the first time we would see it would be when they leaked early images of their smartphone and/or smaller Kindle.