Luger mag ID help.

[ESU]

A few months ago I mentioned in a post that I had acquired a matched 1915 dwm upper with a mismatched lower along with a mis matched p-38 for 300 bux. Part 2 of the saga was the seller promised me a "bunch " of mags for the Luger that he had accumlated over the years. I finally got the mags yesterday. In short he had 17 P08 mags and 1 P-38 mag. The majority of the P-08 mags are WW1 style I guess with the nickel body and wood bottom. Most are numbered. Amazingly there were 2 fxo 37's with bakelite bottoms that are 90% or better. They will go well with my BYF 42.
Now for my question , one of the last mags is a blue body with an aluminum base . The base has no numbers but appears to have an eagle proofmark. ALso on the side of the mag is " Haenel Schmeisser " patent. The mag is about 90% also. I havent seen one of these before and was looking for help ID'ing it. What model would it have been for? I saw similiar markings one time on an mp-40 mag. Any idea on value ? Thx, ESU.