Do You Recognize This Gas Mask Filter?

I am cleaning out Fibber McGee's closet.  I found a collection of gas mask filters, which when I bought the masks were represented as Israeli surplus.  The markings on the filters are in German.  And apparently made by a company called Auer,  The connector is 30mm, and has a strong resemblance to this filter for a German WW2 gas mask.  This may just be a coincidence, induced by similar needs.

If the filters are WW2 era, then the masks, bought with these filters, probably are too, and thus valuable.  Can you enlighten me?