www.925-1000.com

Please give me info about the producer.
I have had this box for many years and I would like to be sure of its originality

To give a 100% correct answer to your question is not easy. However, I try to do my very best:

The box is correctly marked. It has no maker's mark but is assayed by AK. That could be Andrey Kovalsky, active in Moscow 1821-1856. Possibly the assayer could also be Aleksandr Kudrin active also in Moscow 1878-1882. Unfortunately the town mark is badly punched, but could be Moscow. The fineness mark 84 was used before 1882 (its shape). There is no maker's mark (or is there?).
Since the box lacks the maker's mark but is assayed it indicates that it is imported. Before 1882 there was no separate mark for imported goods. Note that there is a Latin S in the engraving NS. Anyway, the customs brought the goods made in gold or silver to the assaying office. The fineness was checked and if it was >84 zolotnik it was punched with the control mark, i.e. assayer's initials. Therefore the maker's mark is missing.

In those days a lot of unmarked German made silver was imported to Russia. It means that the box origin could be from Germany and made before 1882, but that is only an assumption.

Isn't that Alexey Kvasnikov 1811-1838

Well Alexey Kvasnikov was a master not an assayer in St. Petersburg. This object is assayed since it has the fineness mark 84. In addition, I have difficulties to see St. Petersburg's town mark in the badly punched town mark. But as said, a difficult case...

Qrt.S Please write why you think that it has been tested by AK and it is not a manufacturer's mark

Please reread what I wrote or see below

Qrt.S wrote: Since the box lacks the maker's mark but is assayed it indicates that it is imported.

See it this way: Since there is a fineness mark (84) it must have been assayed. The fineness mark is punched by the assayer in the assaying office. In addition, when it has a fineness punch, must the mark AK be the assayer and not the maker. Moreover, according to the Russian law, the assayer was prohibited to punch his mark unless the maker's mark was not already punched. Therefore the AK is the assayer not the maker. Since there is no maker's mark only the assayer's mark, the object is imported. Is the assayer Kovalsky or Kudrin, I don't know because the town mark is a mess.