What is it used for?

This one is a 'SAND GLASS', both length and thickness of which are barely about the same size of my last finger.

Do you have an idea of it? or Can you make any sense? Otherwise, here are some clues for you.

The time limit is 4 min, It has been made by 'Queensland -of Australia- Water Commission' and This one is meant to be kept in a bath.

Have you got an answer? or Still wondering? If you belong to the latter, you might as well think about it while you are having a 'SHOWER'.