As you know,different air conditioner has different width,so,I believe there must be has different air conditioner bracket size for air conditioner.I`d like to know in Europe,what`s width of different air conditioner?for example,9000BTU,12000BTU,what`s air conditioner bracket size it need?
Thanks!
air conditioner bracket (http://www.smartclima.com/air-conditioner-bracket-101.htm)

In America we would measure the width of the air conditioner,, different brand name are different width,,

In my hometown we don't measure anything. Just put the unit in the window, close the window and fill in spaces with whatever you have handy lol.