It is a label that was attached to a stamp commemorating the 35th anniversary of the city of Komsomolsk-on-Amur in 1967. The stamp is listed in the Stanley Gibbons catalogue as Russia SG 3418.
"The town was largely built using volunteer labor from the Communist youth organization Komsomol, thus receiving the name Komsomolsk. However, the construction of the town was aided with the use of penal labour from the prison camps situated in the area." (Wiki)
The label shows a couple of the volunteer workers.
You can see the stamp and label here:
http://home.nestor.minsk.by/fsunews.../su3352.html