Gerni Injector for the Gerni Super 130.1 and the Gerni Super 140.1 hobby pressure washer cleaners. It fits on the HP outlet from the pump, via the short hose, to the hose reel. See it as part 17 in the second photo.
Replacement part will be SKU 128500068
It should also suit the corresponding Nilfisk-ALTO models.
Click&Clean C&C is a method Nilfisk-ALTO and KEW and WAP and Gerni use to connect accessories. There are different Generations and they won't always connect together over cross generations.
See the consumer accessory book HERE