What is the value of a WWII German officers Jacket?

The Jacket is in good condition, its gray wool with red and silver trim (I believe that's an officer artillery) it has four pockets and four front buttons and no other rank emblems. The inside says II./Flakrgt.22 some indistinguishable writing, Max Kohler. I've looked all over google and can't find any further information or pictures that match up. Any info would be extremely helpful as my goal is to rough estimate of value. If a picture would be helpful i can email a picture on request.