So what's with the blue stripe?

[ebeeby]

http://www.ebay.com/itm/Original-WWI-1917-Prussian-Wool-Great-Coat-German-Trenchcoat-Greatcoat-/130724753768?pt=LH_DefaultDomain_0&hash=item1e6fcd7168" onclick="window.open(this.href);return false;

 

[Arran]

The blue stripes indicate it was used in the Weimar era...