What is it and what does it do specifically?
I won't be able to answer until Monday night, so speculate away.
Looks like a Leica prism mount for taking shots on steel that has depressions that match the machined cylindrical parts.
I think the "machined cylindrical parts" are neodymium magnets that hold the prism bracket against the desired ferrous part. What I'm having trouble imagining is the shape of the part that would require that sort of configuration.
The bracket appears to be aluminum. (Could be stainless, but it looks like aluminum to me.) That means the magnets (okay, I'm getting farther out on my limb here) are glued on.
> I think the "machined cylindrical parts" are neodymium magnets that hold the prism bracket against the desired ferrous part. What I'm having trouble imagining is the shape of the part that would require that sort of configuration.
Probably structural steel, wouldn't you think? The shape that the thing seems designed for is a wide-flange column with very thick flanges, as would be common on multi-story steel buildings. Or possibly a large, boxed, built-up section that might be used on bridge steel.
> Probably structural steel, wouldn't you think?
Structural steel makes sense, but I'm puzzled by the slot.
For that matter, I'm puzzled by the bubble. If I'm right about the magnets, they'll stick the thing in whatever orientation the host iron is in, with no means of adjustment on the tool. Unless the purpose is to adjust the host iron -- rather than just record its orientation -- the bubble would seem to be superfluous.
Or unless the host iron is cylindrical and in a horizontal orientation, with a square face (e.g., a length of round steel bar, with the end cut square, laid horizontally and with the end sticking out into space). The centerline of the prism adapter appears to run tangent to the cylindrical magnets below the prism, so if the bracket were placed on the steel bar with the magnets in the short side of the L against the bar end, the bracket could be rotated about the bar's centerline until the bubble was plumb. That would allow the prism to locate (with a known vertical offset) the end of the bar at its uppermost point.
That doesn't explain the slot, though. I'm still trying to envision the application...
Looks like a Wild prism mount for monitoring settlement or wall deformation. I made something similar out of angle iron and a 5/8" bolt with a Wild adaptor, no level bubble, as I had one on the mini prism assembly.
From the position of the post that holds the prism, I'd have to say that it's a bracket used to locate the edge of a structural steel member (or, actually, any outer edge).