It contains all time zones along with their UTC offsets. Time zones can be searched by location name or by UTC offset. Using the index number, a time zone can be selected in both the Location A and Location B combo boxes. For any given time in Location A, the application can calculate the corresponding time in Location B. The local times of both locations can then be compared in terms of day and night. To enable this comparison, the sunrise and sunset times for Location A and Location B must be provided.