| Binoculars by the brothers Koristika|
image by Marco Leone (Image rights)
Koristka was an Italian optical company, based in Milano. It was founded in the 1880s and the full name was Fratelli Koristka. They made binoculars, microscopes, and some camera lenses. Among them is a Victor 55/3.5 in Leica screw mount for the Gamma (Italian Leica copy).