I finally found some pictures of another authentic armband with the same features! This one was found in a grouping of SS items. It was made by the same manufacturer as mine (#10), and has the same 3-line stitching. It even features the same circular stamp of the manufacturer's seal! It only differs in that the two pieces of the swastika were applied in a different way (on mine, the piece of the swastika with the "top" and "bottom" arms was applied first, and the piece with the "left" and "right" arms was applied last; in this example, that was reversed). How's this for confirmation!?