This is an early 1940's British army or other forces 30 hour pocket watch with a 19 ligne movement. Simply engraved on the back GSTP and a broad arrow. This is a pre-series movement with no number. there is a military adoption stamp inside which we can not read. The case is 3 piece snap together made of brass or nickel plating. The case is approximately 52mm. There is one repair mark in the back which has a broad arrow with an F under it. This movement has been cleaned but not timed. Please note the early style of screwed on dial with mock enamel finish and the brushed rhodium finish and a smooth rimmed balance. This watch does not have an external issue number. This is one of the earliest ones produced.