I inherited (from a building contractor buddy) a small
tool/device. I can't post a photo here, but the visually
imaginative readers can picture what I mean from the
following description.

It is cylindrically shaped, about 1.5" diameter, 6" long, in
a metal case. Lens at each end. Acts as a low-power
telescope. The top of the device has a bubble level, with
optics such that when standing on one side of a room, and
looking across it, one can not only see the other side of
the room but also the bubble level and a horizontal marker.
One can raise and lower the angle of the device so as to get
the bubble in the center of the markings, and that allows
the user to see, on the far wall, what is exactly at eye
level.

I don't know what building or other application would call
for such information, but that appears to me to be what the
device is designed for.

My question is: What is this called in the trade? In what
trade would that be? Surveying? Plumbing?

Corrections to my understanding, and other comments welcome.


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CWLee
Former slayer of dragons; practice now limited to sacred
cows. Believing we should hire for quality, not quotas, and
promote for performance, not preferences.