1915 Periscopic Prism Company Ltd. Sniper scope, used on Enfield SMLE (serial n° 6133 Y) during WW1. Even if several scope models were used by the United Kingdom during WWI, the 1915 P.P.Co was the most used by British snipers.

 

Below : a black & white picture showing snipers of the King’s Own Regiment in Salonika, possibly June 1916.