Received today, air quality not too bad. The big problem is that I expected to find, like your other gauges of this kind that I have seen, a single object with the top container up and down 4cl 2cl. However closely the two are not together, which makes two pieces instead of one. Which for me is a big problem (more easy to lose, much less practice ...). Disappointed on this point was not clarified and that deserves to be.