Pocket bubble circle sextant made by G. Felsenthal and Sons, Chicago, Illinois, about 1946. Signed on the front of the frame: G. Felsenthal & Sons Chicago. Marked on the front of the frame: Bubble | Circle | Sextant | Bureau of Aeronautics, U.S. Navy | F.S.S.C NO 88-S-340 | Contract no. NOa(s) 1819. Four quadrantal plastic scales from 0° to 90° every 1°. No vernier. Circular plastic frame with a clear plastic sighting circle, carrying two white plastic folding sights. The back of the frame holds a bubble level and a folding mirror in a plastic housing. In a fitted oiled cloth wallet, containing a transparent plastic 6 inch ruler (broken); other contents are missing.