All About Pocket Knives

http://cgi.ebay.com/NM-VINTAGE-HENKELS- ... dZViewItem This knife is on ebay. I can't tell what the odd tool is used for? Anybody got any ideas?

first, it's not a henckels. manicure blade? what's the square hole in the handle? not a skate key. i looked up the tang mark, j. eichel, solingin, in all my books, not there.
henkle, dusseldorf is a major company based in dusseldorf, banking, manufacture, etc.

eureka- levines 3rd, pg 267. used to install door latches.