The FUBiS student identity card identifies you as student of Freie Universität Berlin and entitles you to various discounts. You need it in the Mensa to get your meal at the student price. You also need it to use the libraries. In addition, you can receive the student discount in many cinemas, theaters, museums and other venues if you show your student ID. Please note that there are no discounts on Berlin public transportation tickets/passes for short-term student.