LOMO (KMZ) lens RO56 2/35mm, T/2.5, Konvas OCT-18 mount, #000592
The lens was made at KMZ in early 1950's (#000592). F=35mm, f/2, T/2.5.
This is 7-elements anastigmat. Resolution in the center is 50 lpmm, at the edge - 25 lpmm.
Mount is so called OCT-18 - for Russian 35mm film movie cameras Konvas-1M.
Aperture ring is tight in T/2.5-4 range.
Some dust inside.