Circa 1928 Glasgow Import marks.

Heavy caseback due to good thickness.

Screwed bezel and back. Threads seem pretty good. Some light engraving to the case rear - mostly illegible and would polish out if necessary.

Crystal is plexi and has a few marks that would polish up fine.

Fits 12 Ligne movements similar to IWC Cal 63 / 64. Omega 26.5 SOB T1-T3 and Cyma 214-236. <~~~~ These three usually fit these cases without modification. Pretty much any standard 4mm thick 12 ligne movement will likely fit. Back then, you chose your movement and then chose your case.

31.8mm diameter without pendant tube.

Ref BD3