This foam lance is ok?

[iautoinstrument]

I bought the Avatar foam a while back, and now that I've gotten more into autodetailing, I'm looking buy a pressure washer to reduce the potential for swirls on my paint.

That is the foam gun I have, and I tried to hook it up to my friend's GreenWorks pressure washer but it didn't fit properly.

Is there something I can buy to connect my avatar to a pressure washer? Or would I have to buy a foam cannon in order for that to happen? I'm currently looking at a Karcher 1800 PSI pressure washer by the way.
This one is ok?