The Crimea Shield (known as “Krim” Shield to collectors) was awarded to German soldiers under the command of Generalfeldmarschall Erich von Manstein who fought and conquered Crimea (Krim in German) in between September 1941 and July 1942. The Crimea Shield was instituted on 25 July 1942 and was the most widely distributed of the shields with approximately 250,000 being handed out.
From 21 September 1941 until 4 July 1942 German soldiers faced severe opposition from the Russian army while attempting to capture the important Black Sea ports around Sevastopol.
This particularly difficult campaign was recognized in the form of the Shield.
I have posted both of mine here so you can see how the back plate is formed.