Circular saw blades for use w/ Rotozip ZipMate?

I'm looking for a circular saw blade (fine tooth preferred) for use cutting wood with a RotoZip with a ZipMate attachment.

That is, blade size = 3 3/8 - 3 1/2, 10 mm or 3/8 arbor.

Alternatively, an adapter that converts the common circular saw arbor size(s) to the 3/8" arbor size used by the ZipMate would also work.

Can anyone suggest a source for either of these? Any suggestions would be greatly appreciated.

(I have of course tried a web search, but am not having success so far.)