The Beseler Beslar 90mm lens contains coated and color corrected optical glass elements, and an F-stop range of f4.5 to f22. This lens is used when working with 6 x 7cm format negatives.
It's iris diaphragm has click stops. The rear is a 39mm (Leica) mounting thread and includes a lens cap and jam nut.
Economy lens for 6x7cm enlarging.