Thanks for your help, Swing...I suppose that you refer to the SA-Kuva image 57056 (the first image of my post of 09 Apr 2015), no ??Swing wrote
Light armored cover M/40 for 7,62 mm "Maxim" machine gun (likely). Weight about 5 t, stuff - 2 men. Manufactured by Karhulan konepaja or Wärtsilä.
I think the other image of that post shows a different cupola, with a openings more narrow ( for observation ?? )
Here another image from SA-kuva archive (81865) of a Light armored cover M/40, although with 5 holes in each nerve instead of 3. It also seems a little higher than the cupola of my previous post...
Sturm78