Is this an air vent?

28W

I'm not a pro . . . just a homeowner. This widget is atop the low loss header in my system. It doesn't look like any air vent I've seen before (which is not saying much, I know). If it is an air vent, where does the air come out? It all looks pretty tight to me. Thanks

SWEI

Looks like a SpiroTop

http://www.spirotherm.com/docs/brochures/Top-2B.pdf

28W

It does indeed

Thanks!