This comes with a male quick connector, and it fits most other gasoline pressure washers up to 3200 PSI & 2.7 GPM.
That would include your Generac unit as long as it's 3200 PSI or less.
The circular brush at the bottom keeps the spray from splattering. It doesn't pop out, and it shouldn't get that dirty since the surface cleaner hovers above the surface.
For best results, spray deep dirt off the surface first, then use your surface cleaner. That will give you smooth, even results and help keep the spray jets from clogging.