The are almost certainly 48mm Sachs.

So bike probably has Sachs/Ohlins. Is that a "standard" version right? Flywheels on standard/6days are the same or the only difference is the stator?
Thank you all for your responsiveness!

Well, yes, Sachs/Ohlins was surely one of the combinations at that time. I think they offered different combinations in different markets. As Jacob 'Berg pointed out above, there were 3 different forks in use, I presume that was in the US market. Jacob told us that the Sachs were used in the base/standard model there.

I don't think there was any difference in stators or flywheels in 2011.
The difference (apart from the suspension) between the standard and six days models were mainly cosmetic. The SixDays was more "completely" equipped, with some protection under the engine etc. Perhaps another type of handlebar.
But this was 10 years ago, most of these parts will have been replaced several times if the bike has been ridden off road for 10 years. So what's important (in my view) is the state of the bike that you buy. Does it seem to be well maintained?
One word of caution regarding the Sachs forks; I fear spare parts can be a (even) bigger problem there than the Marzocchis, but I don't know. I have a son with a Sachs-equipped EC300, he has not needed any spare parts lately :-)

It seems to be well maintained. I am skeptical about what I'll see when the mechanic opens the cylinder. I hope it will be ok.
Owner has changed the fork-suspension springs with harder ones.
My weight (85kg) is for 44( is this number a kind of hardness?) springs.
This is the 2nd owner and with my turn I'll become 3rd.
Forks and suspension had a service when the current owner bought it but I don't know what does it means. What does include a fork/suspension service? Some oil change or what?!

I believe that the 2011 base model had Sachs suspension, front and rear. The shock should be easily identified by the red reservoir.

Back suspension is Ohlins

The 44 is the stiffness of the springs, aka spring constant. 44 is actually 0.44 kg/mm. Higher number means stiffer spring. If you are interested in the physics, take a look here:
https://en.wikipedia.org/wiki/Hooke%27s_law

Fork and shock service usually includes replacement of oil, sliding bushings and seals, plus full cleaning of all internal parts. I do it every 40-50 hours or so. Ohlins states every 25 hours for some of their products.

I am studying in the second year as a mechanical engineer :D. 25 hours is quite frequently. Should i pay attention to anything else on the bike before buying it?
Subframe or something else?
Thanks for your response guys