Tunggul is an archaic term used to describe a specific type of flag or pennant found in Indonesia. It is also known by the names umbul-umbul or rérontek.
These flags are constructed from strips of cloth with their longer side attached to a pole. They are integral to the traditional cultures of Java and Bali, where they are utilized for decorative purposes and carried during various festivals. Additionally, red and white umbul-umbuls are displayed along streets throughout Indonesia during August to commemorate Independence Day.