In Southeast Asia, the slit drum that may wake people for suhoor during Ramadan is called a kentongan.
A kentongan is a hollow wooden or bamboo instrument with a slit cut into its body. When struck, the vibrating shell produces a loud, distinctive tone. Because it has no stretched membrane, it is technically an idiophone rather than a true drum, even though “slit drum” is the familiar descriptive term. The instrument is especially associated with Java and other Indonesian settings.
During Ramadan, communities may use the kentongan to rouse people for sahur, the pre-dawn meal eaten before the fast begins. Its communal role reflects older Indonesian systems in which wooden signal instruments conveyed warnings, announcements, or calls to gather. It should not be confused with the bedug, a large skin-headed drum used at mosques, or with a gong. Customs vary by locality, so the kentongan is a traditional possibility rather than a universal Ramadan practice across all Southeast Asia.