Amazon product just bought one similar to this, you can completely fill the system and allow it to burp. It also allows you to fill the tank and bring the level up so you can run the engine upto temp and watch for bubbles!!
I did this with a normal funnel with rubber around its neck on a clients 38' that had blown a pipe off.
His case was an original pump and missing radiator bleed tube.
I ran it for around 30 min with the funnel until I was happy it was throughly bled and 0 bubbles coming up into the funnel.