On the Zorki, the Industar-50 succeeded the Industar-22, first in collapsible version, then with different shapes. This one is the latest version.
The "aluminium" version.
The Zorki version is the same as the one for Zenit M39, screwed on an extension tube, and provided with an internal tube for coupling with the rangefinder.
We go back in time with this telescopic version. The Industar-50 were manufactured by KMZ, LZOS or KOMZ. This one is a LZOS.