The Industar-37 has a focal length of 300mm and a maximum aperture of f/4.5. It stops down to f/64. This particular example was made by KOMZ in Kazan. It was the lens that was principally used with 18 x 24cm FK and FKD cameras as the lens does not have a focusing mount.
David Tomlinson.
Found a 71 copy, on a focus mount in 39mm, all the lense (top part and focusing barrel) are painted in a sand colour. No distance scale on the focusing barrel
photos coming