Magnification of the scope of Hs-129 B-3

What is the magnification of the sight for Hs-129 B-3, a relatively obscure question?

Apparently used the ZFR-3A gunsight (as per Armed and Deadly - Henschel’s Hs 129), which looed like below. Ca’t find any info about its magnification tho’, or the ZRF-4A which appears to be similar.

image

the zoom is x4.