Greetings Daniel -

Sorry to have had to wait so long to get back to you concerning your question of the colored triangles on G/K 43 ZF 4 sniper scopes, but here is your answer.

Quoting from Peter Senich's outstanding publication, "The German Sniper 1914-1945", page 328 about the markings on the ZF 4 scopes -

"Manufactured by Voigtlander & Sohn ( ddx ), Opticotechna ( dow ), and J.G. Farben-industrie ( bzz ), the sights bore the manufacturer's production mark, the ordnance designation "Gw ZF 4", a white, green, or blue triangle to indicate reliable function limits of each device in various climates, and a production serial number. Although the aforementioned markings appear to be the most frequently, specimens have also been noted bearing a "G43", "K43", "ZFK 43", and "KFZ" designation as well."

Now, the white triangle indicated favorable operation under standard weather conditions, the green triangle favorable operation under the extremely warm tropical regions, and the blue triangle favorable opertion under the extremely cold conditions encountered in areas such as Russia and the Scandinavian countries.

My own ZF 4, original wartime production is an example of the much rarer, and harder to come by Opticotechna ( dow ) manufacturing company with a blue triangle. Very tough to get. In fact, I traded with a friend of mine who owns a K43, now with my former Voightlander & Sohn ( ddx ) scope with white triangle.

Hope this helps answer some questions for you, and again, sorry about the length of time it took me to get you the answer. With my job, it will cause me to have to create pauses at times here.

Bill