I will email Subal on this if I can't find out but thought someone might know off the top of their head.
How do I work out if I have type 3 or 4 subal housing port mount? From the guide on reef photo (http://reefphoto.com/kb.php?id=21) I would be type 4 according to internal diameter (110mm) but my mount is not tapered like that.
From memory I am type 3 but I can't find any of the original purchase paperwork. I bought the housing early 2009 if that is any help.