Originally Posted by
meFIRST
For people who can't read cyrillic, its the Russian Internal Passport, a relic of the Soviet era, which to this day, as a foreigner I still don't quite understand. Ditto for that 7 day (formerly 3 day registration).
Russian internal passport is essentially an equivalent of other countries' identification cards. It is not actually a passport, the name is deceptive and inherited from Soviet and imperial times.