The yellow colour of the optic is often connected to the use within Rommels Afrikakorps. In fact the yellow colour was ordered to be used on new optical equipment made after september 1943. There even was an order that all present optics had to be repainted as from that date. We have seen many glasses in yellow that have indeed a simple overpaint, also we found new pieces that were never even close to Africa.
These yellow periscopes for an armoured cupola were never meant to be used in the desert.
The word “Panzer” is common in the German designations of Bunkeroptik. In this case it means “armoured”. To obtain a better price on auctions, these pieces of optics are often sold as pieces related to the second meaning of “Panzer”, which is of course the tank.