Ergonomics from another planet.
It makes rich foam and generally does everything it promises, but the moment you pick it up in your hands, before you know it, the container has fallen to the ground, with all that entails.
For it to connect to the water gun, the corresponding modifications will have to be made so that it doesn’t stick and the yellow plastic doesn’t remain stuck on the gun.
The conclusions are yours; only patience.

I see an attachment without a container and it does not come with anything else because it simply works with the existing cleaning containers you already have, that's why if you don't have a container, you prefer the complete set. The yellow button on the side makes a difference. On 23/11, personally, I got the attachment with the container, you open the valve all the way and the liquid sticks everywhere, all white, liquid for stone.

The nozzle came without a container and without a cleaning liquid. Also, for older Karcher washing machines before 2010, the "Karcher Adapter M 2.643-950.0" is required because otherwise it does not lock onto the gun. On the positive side, the one-liter containers with Karcher's cleaning agents and foams easily and quickly fit in and out by pressing the yellow button on the base of the device.