Hi, that is one of my units. Hope its working great for you. What happens is what was said before. The wort passing through pulls a vacuum through the holes & areates the wort. You need to leave it above the wort though. & watch out because it will foam up big time in the fermenter. So if you use a fermenter just big enough you may need to sumberge it towards the end of racking so it doesnt foam out of the fermenter.
The wand is just a little bonus feature that goes with my counterflow chiller. It is nothing fancy but it does kick butt!! Let me know how it works for ya!!
I do have them on my website but not on ebay at the moment.
Hoppy Brewin!!