O Level (Ordinary Level):

1. Age Group: O Level is also typically taken around the age of 16, often at the end of the fourth year of secondary education.
2. Historical: O Levels were historically used in the UK and some former British colonies, but they have been largely phased out in favor of GCSEs and IGCSEs.
3. Grading: Like IGCSE, students receive individual grades (A* to G) for each subject. O Levels used a similar grading system to IGCSE.
4. Recognition: O Levels may still be used in some specific educational systems or regions but are not as widespread as IGCSE.