German medal to be identified

[battle of loos]

good morning,

 

I need your help to identify the decoration that one of the soldiers wears
 

1 Art Mun Kol 117 ID - 28 mai 1915 - Sallaumines (near Lens)

May 28, 1915

 

during the fighting of May 1915, this unit was on Souchez.
present at Loos during the British offensive of 25 September 1915

 

here's the picture :

 

 

 

soldier :

 

 

thank's in advance.

 

regards