Special military production Zeiss Ocular 30x / 40x, wide angle and with a milliradian reticle.
Reticle is a traditional mildot added with a stadia-meter ranging scale. (1m tall and 0.5m wide target).
Designed for the Zeiss Diascope 65 in which the oclar provides fixed magnification of 30x and the reticle is in correct proportions.
Very rare and hard to find piece of superior optics!