Gerni pressure washer solid brass screwed coupling for lances and adjustable nozzles. See it at the top right on the lance in the second picture.
This is OLD obsolete stock and is sold "as is" and the purchase is the buyers responsibility to ensure it's correct for what they want to use it on. No refunds. no warranty.
Maximise the saving on postage and buy some of the related pressure washer parts below, or parts such as filters for your Nilfisk or ALTO vacuum cleaner, or a new floor tool and hose.
At the moment, standard postage within Australia is capped at a maximum of $20!