Unissued Original German WWII Kriegsmarine Blocking Weapon's Mechanic NCO's Career Sleeve Insignia

Unissued Original German WWII Blocking Weapon's Mechanic NCO's Career Sleeve Insignia-The insignia consists of a vertically oval, deep navy-blue wool base with machine embroidered naval mine over a multi-cogged gear wheel superimposed on a vertical anchor which is machine embroidered. Cloth backing is intact.