Schneider Shutter Size

[Fotoguy20d]

I was looking on Schneider's website. They have a table of data that includes something like this:

Shutter Size II 5/2+3 (ref: here (http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses/symmar/data/5,6-240mm.html))

What does that mean? I'm assuming the II means a Compur 2 but what's the rest of it? How would this shutter differ from a II 6/2+3?

Thanks,
Dan