During the actual measuring I have seen with a professional, what can "the" device :)
Measurements warning extremely reliable - a deviation we could not make really determined.
Having just measure around 5 corners in 4 rooms carpets musste- I am absolutely satisfied with
the handling.
Of course, an even more significant would to all corners have more fun with Flächenberechnungne,
but I did not want to spend more on "the" device than for 150 ² carpet :)
Conclusion: Best for the price - exactly - handy - could not be better!