Pretty small and easy to handle

I have the device since yesterday (via an online pharmacy because cheaper) and am very happy with it.
It's super easy to use and to clean and self-explanatory. When attaching the "traffic light" I had to think a moment, but then the 3 sticker could easily click it. Nice that each a "spare sticker" for the 3 traffic light colors was still attached.
And very practical is also the additional mouthpiece for those to whom the opening is too large.
Update 23/11/2014
Unfortunately, the device has become faulty and shows jumps of up to 250 points between 2 measurements. I'll return it and hope that I just had bad luck and a Monday device got. In the other, the problem seems to be not occurred so. Therefore, only 3, instead of 5 stars.