If you want to get rid of it I'll take it. FReepmail me, I'm serious.
Are slide rulers difficult to find? Right after I posted, I took mine out of the drawer and compared it to a picture on Wikipedia. I don't think what I have is a slide ruler after all.
Mine is a "metric converter". There are photos of metric converters at the bottom of this site:
http://www.eyrie.org/~dvandom/slide/slidegallery.html
Whatever it is, I can't give it away. I think it might've belonged to my father. I've been holding onto it figuring my sons can use it with their math lessons eventually... maybe they'll figure out how to use it. ;-)