What is this tool?
 

http://home.mindspring.com/~dforcier/biketool%203.jpg

Looks like a grabber for cantilever brake arms to me. How is it used?

(Pardon the pic. It's off a scanner.)

It's a third hand.

It's purpose is to hold your brake pads closed against the rim while you tighten the brake cable.

Thanks. One more thing.

As the lower handle wire crosses the inner "grabber", it turns - heading into the picture - around the vertical wire then comes back toward the handle at 45°* and forms a hook. (Sorry, can't photograph it.) Does that serve a particular purpose?