The overflow is a special opening located at the top of the shell. It prevents the transfusion of water over the edge: reaching the overflow, water through a special hose enters the drain pipe, which saves the bathroom from the «flood». Such a hose may be part of the wash basin, but most often it has to be purchased separately.
Note that
overflow is designed for situations when the drain itself is closed (for example, by plugging); but if the drain is clogged lower (for example, in a siphon), this function will be useless - the water will still have nowhere to go from the filling shell. And therefore, the presence of overflow in the design of the wash basin does not eliminate the need to monitor the state of the sewer.
There are many national stereotypes: many users find certain countries more attractive than others. However, nowadays these stereotypes are practically unfounded. Firstly, in the country of origin of the brand, often only the headquarters of the manufacturer is located, and the production may be located in another state. Secondly, the origin of a certain country is not yet a guarantee of quality: it all depends on how carefully a particular manufacturer controls its products. Therefore, to assess the quality, it is worth focusing not on “nationality”, but first of all on the reputation of a particular brand and the price category of the product. Among the countries represented are the following:
Belgium,
Germany,
India,
Spain,
Italy,
Poland,
Portugal,
Slovenia,
USA,
Turkey,
France,
Czech Republic,
Switzerland,
Sweden,
Japan.