Among the various insignia of the stormtroopers, copies numbered according to separate units are the rarest. The standard assault badge of the Gurschner company was also made in an extra version for the members of the 21st assault battalion. On some copies of the general insignia, the background of the skull sometimes has an anodized, metallic sheen. In the case of badge 21, it was clearly painted in a reddish color.
The 21st Assault Battalion was a troop unit of the 21st Division. The 6th, 7th, 8th and 28th rifle regiments belonged to this division. These were regiments from the Czech and Moravian parts of the Monarchy with mostly German-speaking crews. According to the basic organizational rule, a crew of one company from each of the four regiments was transferred to the assault troop, which then basically operated as a divisional unit. Storm Badge 21 is one of the rarest and most unique badges.