VEVOR 22" Pressure Washer Surface Cleaner, Stainless Steel Pressure Washer Attachments with 4 Wheels, 4500 Max PSI, 3/8 Quick Connector, 2 Spray Nozzles, Dual Handle, for Concrete, Patio, Sidewalk

I have a nilfisk alto 140.2 high-pressure cleaner that I want to use for this. But I have looked everywhere on the internet, including on vevor, for a transition piece or adapter so that it can be successful. Do you have such a transition piece or adapter so that my nilfisk alto can be connected to this patio cleaner I just bought from you? Alternatively, which high-pressure cleaners can be connected?

Where does the O-rings go.? I can’t see it in the manual.