Hi ViS
OK, I'll take a guess, 18th Landwehr Infantry Battalion, 3rd Company, 154th weapon. During the 1870/71 war the 3rd Reserve Division contained several units with designations such as, Combined Landwehr Rgt 6/18, or, Combined Landwehr Rgt 18/46. Perhaps Joerookery or Glennj could add more to this..
Larmo