This is also a Creagh-Osborne marching compass. A difficult item to research, it is thought that this instrument was manufactured after 1929 as an improved version of the similar World War I model. One looked through the lens sight to determine azimuth, and used the sights to align it with an objective. U.S.E.D means United States Engineering Department.
Contains Radium paint. (0.7 micro sievert/h)