Crazy small bar open 24/7 since July 7th 1979 (it closed once for three months).
If you want to have a bite of the old time Berlin you have to spend one night drinking in this smoky bar, possibly playing “kicker”(table football) with some locals.
Bier is cheap but not best quality. They also serve wine and cocktail (but also not best quality).
Best time to go is late at night after you already had some drinks somewhere else.