Pete C. wrote:
....

The specs are related to the quality of the bubble levels used in the
units, the quality of the factory alignment of the mirror or laser
mount, etc., not the laser beam itself. The laser beam will spread a bit
with distance, giving a larger spot size because the beams from laser
diodes aren't as well collimated as those from other types of lasers.

Precisely--the accuracy is in making the mounting precise and the
ability to level the unit itself accurately. The cost is in the
machining and other manufacturing to get precision and accuracy there.
The whole device relies upon base leveling and that essentially boils
down to the equivalent of a spirit level--it costs bucks to get the
precision required to translate from +/- some relatively small number
over 100-ft, say, to the equivalent over the few inches at most of the
length of the base. The laser itself is the almost trivial
part--straightline propogation of the light beam comes for virtually
nothing comparatively.

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