Removed hopeless whirlybird, and as per another review it did fit the whirlybird flashing (added some silicone around it for extra sealing),
I do have a tiled roof, house is approx 315sqm ,two vents in eaves ( old whirlybird vents), and yes it has made a noticeable difference, I will be purchasing another one and another two vents to really get the air moving,
One thing though you can hear it doing its job, with no ambient noise, sounds as loud as the loo exhaust fan if you left it on and not in there( no big issue),
Delivery was quick with no issues.
Recommend...yes