Clapsticks

Clapsticks or clappers are a type of drumstick, percussion mallet or claves that belongs to the idiophone category. It serves to maintain rhythm in Aboriginal voice chants. Unlike drumsticks, which are generally used to strike a drum, clapsticks are intended for striking one stick on another.

As an ancestral instrument that may traditionally accompany the didgeridoo, it is sometimes referred to as the musicstick or just stick. In the language of the Yolngu Aborigines of Northeast Arnhem Land, near Darwin, Australia these clapsticks are called bimli.

Traditional clapsticks are made from long branches hollowed out by termites. They can be individually decorated, and there is no standard size.

(I have some doubts about the information presented "Traditional clapsticks are made from long branches hollowed out by termites" . Didgerdoo that are traditional made are made from termite hollowed branches but all the clapsticks I have seen are solid. However Australia is a big place with I believe approximately 300 or so traditional languages were spoken. So it is possible some groups made them from hollow branches)

Boomerang clapsticks are similar to regular clapsticks but they can be shaken for a rattling sound or be clapped together.

The usual technique employed when using clapsticks is to clap the sticks together to create a rhythm that goes along with the song.

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Wikipedia