Soviet canvas hat used by Destruction battalions of NKVD troops

Soviet canvas hat used by Destruction battalions of NKVD troops - often called "destroyers". Clear marked with military factory stamp and dated inside 1941.  Exact this type of hats has been used by Destruction battalions of NKVD in Estonia in summer of 1941, when these battalions were sent to clear the territory from the enemy saboteurs and spies who used the soviet uniform. The destroyer troops used the blue tankman coveralls, other unusual uniforms and these kind of headgear  to recognize and  differentiate each other in close combats in the forest and other places, where saboteurs could be be mixed with destroyers, due the same  Red Army uniforms. We are not sure for what purposes these hats were produced originally, but we never seen other photographically evidenced use of this hats than the NKVD destruction battalions. At least these are not navy hats and these are not a civil or worker's hat, due the military type of markings on it.  It's a minty hat made by factory Nr 7 in Gorky and 59 size marked.  As known this  factory produced only military uniforms by contract, not civilian. We have few hats in stock.