A periscopic eyepiece attachment connected to a telescopic night sight moed on a small caliber weapon to move the line-of-sight of the telescopic night sight to the line-of-sight required for the day sight (iron sights) of the weapon. The periscopic eyepiece is intended for use primarily with the much...http://www.google.de/patents/US4582400?utm_source=gb-gplus-sharePatent US4582400 - Periscopic eyepiece for small weapon telescopic night sights
