I linked directly to his store above.
/eidt/ also note that he says he's not doing international shipping any more :-/
It occurred to me since I last posted, that if Sonnet could have made one Overdrive that physically fitted both the 650 and the 475/605, they surely would have - much cheaper than having two separate production lines, packaging, marketing etc. So I wouldn't recommend gambling on that one fitting a 475/605, unless you're willing to take the chance it'll involve major hardware hackery.
To my shame, I have not yet installed either of the two I bought from him :-/ I'll be sure to post a report when I do.