Not sure what you call this tool but it allows you to put pressure in opposite directions on the pads with equal force. I needed to use the pressure to press in the bronze shifter bushings into the shift rod coupler in two directions at one time. Thinking it was a 70's version for pushing brake caliper piston back in. I have used in on several occasions for odd jobs requiring equal force.

Mark...that's exactly what it is....pad spreader

I agree, primarily a pad spreader. I have used it when rebuilding calipers for 30 years. My tool is identical to yours.