What a great idea this is.  The water meter lets you know how much water is used in the yard, or just cleaning the car.

It is a spray nozzle with an integrated water meter and has 4 spray settings.  The ‘Save a Drop’ Hoze Nozzle can be purchased right here for NZ$33 plus shipping.  The only problem is I am not sure if it fits our hose thread.  Perhaps worth an email to them to check.