What must competitors bring for both rounds of the event?

Competitors are required to bring a personal electronic device that is on battery power because this allows them to access necessary digital resources and presentations that may be needed during the competition. Such a device can provide essential information, assist in research, or help with presentations and communication during both rounds of the event. Having a fully charged device ensures that competitors can participate fully without facing technical difficulties.

The other options, while relevant in certain contexts, do not universally apply to all competitors. Extra costumes might be needed for specific events but are not typically a standard requirement. A professional portfolio may enhance a competitor's presentation but is not always mandatory, as it depends on the specific guidelines of the event. Printed materials could be useful for distribution but again are not necessarily a requirement for all participants.