Hello! This my first post about a certain relic. I found and bought today the aformentioned canteen, which really looked to me like a M31 German field canteen. I post this here, because, apparently, this is not a German canteen. It has several design details, which differse it from a German one and the cup is made of aluminum. Markings are only present on the cup and the buttons, after taking of the leather piece and the cover, no markings were found. Also, the cap appears to have been altered in some way. It could be from some other Axis country, or it could be a Bulgarian canteen, since i bought it in Bulgaria. Can someone identify it?
Identifying a German M31 look-a-like canteen
Identifying a German M31 look-a-like canteen
Identifying a German M31 look-a-like canteen

"Handywork" on the cap
Identifying a German M31 look-a-like canteen

Marking on the cup
Identifying a German M31 look-a-like canteen

Markings on the buttons
Identifying a German M31 look-a-like canteen