A.B. (Aktie Bolaget) LYTH is a Swedish company founded in 1861 by Georg Wilhelm Lyth. Lyth manufactured in the 1920's-1930's marching compasses for Sweden's Army.
Before he founded SILVA, Björn Kjellström worked together with Lyth. Silva sued Lyth later because of a patent filed by Lyth in 1931 for a fluid-dampened marching compass. ( Info courtesy Compassmuseum.com)
No serial numbers. No military stamps, no date. But since the base of the compass is made of bakelite, I guess it was made during the 1930's. It also has a gradation in 400 gons.