I bought this about a hundred years ago at Sears Roebuck. Its an adjustable drill press vise. As you can see it can be used vertically or horizontally. I drilled a 2 x 12 to accept the vise in longways or cross ways. The bolt heads are counterbored to fit below the wood surface and will fit flat when clamped to a table top. I use those Irwin speed clamps for this.
This is a most handy item for simple parts fitting or barrel turning.
Saw something that gives me a good laff, a few years ago I worked on a "rodeo cowboys" truck and while inside I noticed a set of spurs ...with L and R in black felt marker on the inside :-D :-D . Makes me wonder if he had to write what boot they went on on the inside if he was smart enough to put it on the inside so it wouldnt be seen or if he just got lucky