You can choose the monthly amount you wish not to exceed outside of what is included in your subscription and/or your add-ons. This typically concerns your calls, SMS or mobile internet sessions beyond what is included in your subscription but also for example international calls, to premium numbers, while roaming in non-EU countries. If you reach this chosen limit, your out of bundle consumption will be blocked until the end of the month and automatically restored on the 1st of the following month.