From the list: Bush Bass Resource

The Washtub Bass Page Clearinghouse for Washtub Bass Information. In the Antipodes we call it the Bush Bass or the Tea Chest Bass. The defining feature of the "washtub bass" family, for The WTB Page, is that the vibrations of a string are amplified by a prefabricated container or chamber of some sort (and that it produces notes low enough to function as a bass).