what we do

Name That Thing

As mentioned before, I’ve been unpacking.  Among the hundreds of pencils, the boxes of staples that demonstrate the history of staple packaging and the wealth of leather and decorative paper, I’ve found a variety of things I cannot name.  Here is one:

What is it?
I have no idea

The measurement ticks are 1/8″ apart and the knob turns to loosen or lock down the measurement aspect of the device. The whole thing is 2 1/4″ long and there are hooks on the upper left for attaching it to something.  I’m sure someone out there must know what it is and that I will feel stupid when they tell me.  Anyone? Jeff Peachy?