German Zeiss 3-9 on my 300 H&H froze the erector in the heat of the Kalahari and could not change power. Stuck on 5X so was able to use it. Also, rubber ring on objectice kinda melted off, it was actually secured by some type of two sided tape (couldn't take the heat). Zeiss did replace the unit with a new VM/V which I sold in its sealed box. That rifle now wears a Leupold.