PZB41 empty box 20x187 R Gerlich

Hi I have a question for you I can buy from my friend this empty case it is from 20x187 R caliber? What is the real.value in this condition . Thanks a lot

Here is another to compare at auction and see where the price goes. This fellow had a large following so you can get a very good idea.
https://www.gunbroker.com/Item/790255269