Why is it so difficult to penetrate Russian air defenses?

The modular nature of the Air defense system ensures that the system can adapt to face the most pressing threats, be set up, fired and moved within minutes.

The system can be outfitted with long-range, medium-range and short-range munitions depending on the scenario. Owing to this flattering reputation – Moscow claims that the S-400 are capable of tracking several dozen targets at the same time – these systems are among the flagships of the Russian arms industry.