Veteran Bring Back German WWII Deckungswinkelmesser (Fire Calculator)-Ok, so what the heck is a Deckungswinkelmesser? It is a small pocket-sized optical device issued to artillery and map-reading officers. It was designed to measure terrain angles, calculate distances, and determine height differences in the field. This one is very well marked. It shows light use. A very interesting, scarce piece of field gear with a funny name. It is functional. We were lucky enough to buy this from the son of a veteran. We will supply the name of the soldier to the buyer.