The title, "9V VTech Storio Reading system replacement power supply adaptor" reads like it's a VTech product. It's not, but that fact was actually mentioned in the product page when I bought it. It's just non-obvious.
The first of this product's two problems are that it has a fairly short cord (1m). This makes it almost useless for a child that likes to move around, or even one that likes to read just a step away from the wall socket.
The second problem is that it is expensive for a generic non-branch power adaptor, even more so when you add in postage costs.