I know tag from 1937 and a pre war makers logo

[Garandy]

Aluminum perhaps from crate of gas masks?

[Daarom]

FWBN =F W Brockelmann Aluminiumwerk Gmbh KG Neheim/Ruhr. It could be for many things. But this manufacturer made a lot of canteens. Maybe there was a token attached to a box? C 31 132 canteen model 31 132 pieces? But of course what you say it could also be for gas masks The M31 Canteen and its Variants

[BlackCat1982]

Nice makers batch tag. Reichswehr Adler, nice find.