Looks like it works on the same principle as the S&W front silhouette sights. You are able to pre-adjust the sight for four different distances and select any one of the pre-sets by turning the main elevation adjustment wheel.

Aristocrat makes one of these, but it looks nothing like the one pictured in the OP. Can't find any others. No markings on the sight?

Adios,

Pizza Bob

__________________
NRA Benefactor Member