Trench Periscope 10x20 DOW (​Waffenwerke Bruenn, Prerau Plant, Czechoslovakia), circa 1942

Grabenperiskop (trench periscope), produced and marked DOW, or Waffenwerke Bruenn, Prerau plant, Czechoslovakia (renamed Opticotechna GmbH, Werk Prerau in 1943), in around 1942 and intended for the Wehrmacht scout troops and Scharfschütze shooting positions.

The periscope is made up of a tube with a length of 53 cm, which allows and guarantees the observer a periscopic vision in total safety. At the ends of the tube, there is a 10x eyepiece equipped with a graduated reticle between -60° and +60° and a 20 mm objective lens.

A very rare original vintage photo shows its use.