This is a model number first coined by Edmonds in Australia. It is a hybrid rooftop ventilator that has a 600 mm diameter throat (24 inches). It is also available here with higher performance. The II600 is the same form and function except it pulls far more air when powered. And it pulls air at static pressures greater than 0.1

The Edmonds EP600 fails to pull air at any pressure over 0.1