I would like any information on a cerca 1939 Elgin battery powered pendant watch. 7/8" in dia. Face has ELGIN w/logo under and swiss at bottom. movement appears to be mounted in bakelite. Inside case reads 'cased and timed in USA by witenhaur # 94132'. Movement reads one jewel unadjustable with a # 6820. Watch hangs upsidedown with stem at 3 o'clock position. This watch belonged to my wife's mother and is ingraved Winifred from Mother 4-27-39. Thanks for any help.