Yukon 21031 (6 - 100x100 mm)

Pros: Excellent image quality at a very low cost.
Cons: Product cosmetic is good not great.

I bought this scope as a laser beam expander in a research lab. The image quality reaches theoretical limit of a quarter wave optics. The wavefront quality was tested with a shear plate interferometer through the magnification range 25-100X.

Field test outdoor confirmed laboratory test results. The strength of the scope is the design focus on image quality and not product cosmetics.