Kusul are water containers made from coconut shells. They were sealed with a stopper usually made from coconut fibre which is called Muthai.
The Torres Strait Islanders travelled long distances at sea for trading and battle so it was essential that they carried a plentiful supply of water.
Two Kusul were joined by a fibre rope which was strung around the neck and tied at the waist when travelling on land where there was not a plentiful supply of water.
Like most utilitarian utensils of this nature they were carved with motifs such as the turtles and dugongs seen on the Kusul in the print.