During WWI these monoculars were used at socalled signal- and blink-devices, which functioned as mesaging systems. As the signalling lights were quite weak, so they could not be seen with bare eyes by the enemy, binoculars or monoculars were needed to locate and watch the blinking signals.
The mono has two feet with threads to fix it to the blink device. With a small leather strap was fastened to the feet. The early model still has its mounting screws.
Portovrij? In NL boven € 200,-