A Timer Boundary Event, which is attached to the boundary of an Activity, change a normal flow into an exception flow upon being triggered. A particular time-date or cycle, for example, on Mondays at 9 A.M., can be specified to trigger a Timer Boundary Event.
A Timer Boundary Event displays any of the following on a diagram:
A Timer Boundary Event name if the name is specified.
A Time Cycle property name if the name is unspecified.
A Time Date property if the name and Time Cycle are unspecified.