Clamp Size for Board Racks on a 2008 Moomba Outback V factory Tower

I own a 2008 Moomba Outback V. It has the factory tower on it. I would like to get a couple of board
racks for the tower but I need to know the Clamp size. Any one out there know what I need to order?

1 5/8 i think...dont take my word for it, I ordered the wrong size clamp for my mirror on my lsv...

I think I have heard that somewhere before. Thanks so much.
Lacy

Yes, that is the correct size if you want something that mounts to the vertical tube. If you want something on the horizontal bar like what comes from the factory, then these are what you want:

http://www.ebay.com/itm/Moomba-Four-...32501826918136