Contact Stengler Gmbh in Germany
Email: stenglerGT [at] aol [dot]com
Ask them for technical details...
As Done Fishing said, it is a processor board that takes signals from a small propeller and displays the wind speed.
Google "Windmessgeraet" to get hits for wind speed indicators...
Google Stengler & yoiu will gen many hits on that company...
Google Windmessgeraet" + Stengler and you will find only 1 reference & that is your enquiry as 'Creativ_Pl' two days ago on the same subject in a Polish forum:
http://www.elektroda.pl/rtvforum/topic1005540.html
I hope you get the answers....