3./Aufkl.Abt.4 Erkennungsmarke

The tag or 'Erkennungsmarke' shows overall normal signs of wear. It belonged to a soldier who served in the 3.Kompanie Aufklärungs Abteilung 4. This unit was formed in early August 1939 from Kavallerie Regiment 10. It was part of the 4.Infanterie-Division. This division saw its first combat during the invasion of Poland in September 1939 and then Belgium and France in May 1940. 
In the summer of 1940 the division was renamed into the 14.Panzer-Division and the Aufklärungs Abteilung into Panzer Aufklärungs Abteilung 40. It was put into action in Yugoslavia in 1941 and in the early summer it participated in the invasion of Russia. It fought in areas like Cholm, Don, Mius and Stalingrad. In the summer of 1942 the unit was disbanned and the remnants were absorbed within the Kradschützen Bataillon 64. It participated in the fighting in the Stalingrad area were it was destroyed in Januray 1943.
In March 1943 the unit was rebuild again in France as Panzer Aufklärungs Abteilung 64 and was part of the 1.Armee.  
The 'O' on both parts of the tag stands for the soldier's bloodtype.