Your ticket is aMetrebus Roma BIT. It costs € 1.50 and is valid for 100 minutes from first validation. You can use it just for a single journey on metro/train urban route and for unlimited journeys on other means of public transport within its 100 minutes of validity.

You can buy it at Atac ticket offices, authorized shops, automatic ticket machines (MEB) and through the digital service tap & go ® with contactless payment card enabled for online purchases or via smartphone with the B+ service.