4 stars I forgive is because I am still not entirely clear how the thing works or if it works. We had until now always a smell stone toilet hanging ... which I thought was rather questionable as zudenkend partially disgusting or the environment. The stone comes in an inconspicuous folding plastic wrap and looks in our white ceramic toilet in spectacularly unremarkable ... a plus. We have a vent in the bathroom which is also activated ... once smelled it already partially longer by erledigtem business - despite smell stones. This toilet block but it smells even after switching off the ventilation neutral or to nothing in WC. That means to me that this toilet block but must have some effect. But since I have no comparison how it acts when there is no ventilation, the air can circulate to anything more accurate say ... I have just a guess that there are at least a few minutes to the air needs to "neutralize" - just over it and wash the smell is in nu away ... at least that was not the case with us.
