MOTM

This is a question I should have been able to search up the answer for from the list archives.  When I type in 'screws' and click 'search' on Yahoo, it tells me to type something in the search box, so rather than trying to get Yahoo! to fix their web site I'm just going to ask again.

I need extra mounting screws for regular old MOTM rails as bought from synthtech.com.  What is the exact size for these, and does anyone have a part number at some reasonable retailer?

Thanks much!