The concussion-buzzer 

•The distribution of the concussion-buzzer is very intriguing as it occurs in Luzon, Nias, Sulawesi and among the Orang Asli in the Malay Peninsula. Although this is typical of the Austronesian region, it seems difficult to explain why it should have disappeared from so much of the central area of the Philippines and somehow bypassed Borneo. 

•The concussion-buzzer is made from an internode of split bamboo, with part of the side-wall cut away so that two long project tongues emerge from a cylindrical base.