That's a SNO-M Soviet sextant
, a high quality copy of the highly regarded Carl Plath sextant used by the Nazis in WWII; actually not a copy but the real thing, since the Soviets uprooted the factory and tooling after the war. Read about it here: The USSR SNO-M sextant | The Nautical Sextant
This guy considers the similar SNO-T (a slight refinement of the SNO-M) to be "possibly the finest sextant ever made" -- see: The USSR SNO-T sextant | The Nautical Sextant
Your box lid label is an inventory of things included in the set:
1. Diopter, two of them, in the 8th pigeonhole of the case
2. Correction key, one of them, 9th pigeonhole
3. Screwdriver, one of them, 6th pigeonhole
4. Sextant, one of them, 1st pigeonhole
5. Light filter, one, third.
6. Light filter, one, third.
8. Passport, one, seventh
9. Magnifying tube 7x, one, second
10. Flacon with oil
, one, fourth
11. Flannel [cleaning cloth, I guess], one, fifth
12. Brush, one, 10th
13. Mirror, one, 11th.