Thanks. I also found some here.
http://www.specialtypowerwindows.com...s.php?c=3&t=19
They call them 'splined wiper knurls'. I know they are knurled, but that's knot what I would call them.
I'll remove the one I have and take it to the boating supplies store. Maybe they call it
another name. At $6-9 plus shipping, I wish I hadn't lost the thing and will probably find it next month.