Original U.S. WWI X7.5 Model 1918 Trench Periscope by Wollensak Optical Co. With Leather Case Gahendra Martini Rifles & Parts It also made other products

It also made other products and tools

before being transported to the Italian Front as a reinforcement after the Italian defeat at the Battle of Caporetto

but the maker marking can still be discerned:

temperature and range adjustments

as the hat (with the blue star) was particularly popular with cavalry units

Original U.S. WWI X7.5 Model 1918 Trench Periscope by Wollensak Optical Co. With Leather Case Gahendra Martini Rifles & Parts It also made other productsOriginal item: Only One Available. Measuring 19 inches in length, this is a very nice WWI Era Model 1918 Battery Commanders periscope. In X 7. 5 power, these were used to help view and plot artillery attacks from behind cover, to avoid exposing the commander to danger. The bottom of the periscope still has the manufacturers markings: TRENCH PERISCOPE NO. 10 X7. 5 MODEL 1918 M. F. G'D BY WOLLENSAK OPT. CO. ROCHESTER, N. Y. U. S. A. No. 4517 R. G. C.