Measuring Stick For Art Lovers

I believe I bought this at the Rijksmuseum years, and I mean years, ago.  In any case, I can't imagine any other kind of place where they would sell something like this.

Went to work, worked, went back home, and there wasn't much time to go to Breda, so that will wait again till tomorrow.  I am making sure anyway that the work at school is updated.  I've mentioned it before and for the blog I must say it is a relief.