GOOD NEWS. . . . The PICTURE UPLOAD FUNCTION IS WORKING !!! The tech folks at the parent company have been able to remedy the issue. You can upload pictures once again. Thank you for your patience.
the inner shaft is the same but be careful with the outside diameter. you will hit the anode-trim fin on a alpha if not careful.
you can get a flat one if you have power steering or just break the one you have off.
i have a couple of mirage II vented props that were 15" dia.(i think) after changing the anode to a flat one they worked.
the dealer i bought them from said just break the tab with a hammer. as stated i bought a new flat tab. breaking didnt seem like a good idea.