Good afternoon all. I've been rummaging about in the gun cupboard and came across an old Meopta 6x42 scope. I know nothing about these and wondered if anyone can share their knowledge with me please? I've had it around 7 years.

Scope - https://imgur.com/RdOGNbZ https://imgur.com/UPGFt5e https://imgur.com/63MsYch
Reticule https://imgur.com/v4CAEWf

Any ideas how old it might be?
Are they considered to be good quality? The glass looks good to my ageing eyes.
Where were they made? There is no country of manufacture I can see.
The optics are good but the metalwork has a lot of marks and scrapes as can be seen in the pics, would anyone hazard a guess at a value?

Finally, i assume this https://imgur.com/X4nKMJM is to aid range estimation, but how do you use it, and is is suitable for sub12 air?

Many thanks, Tom