You've got better eyes than me Russ...I could just make it out after you said what it was.
They are handy little beasties...here's one on my low drill table fence:
They have an adjustable nose with a rubber end...you adjust this just like on a Mole wrench until it just closes firmly:
The cheap ones tend to pop open so try to get a good one.
You can get a variety of orientations..ones that clamp down, others that push against things...I got mine on FleaBay...cheapest way of buying them IMHO...try CLICKING HERE