1927-1928 Roamer 15 Jewel MST 175 Trench Watch

This is a 15 jewel, MST 175 in a Sterling Silver paris square case - with full width wire lugs and is often associated with aviator's especially when with a black dial. The paris square watches were worn on a wide conventional strap, whereas the more comon 'bascine' round case with narrow wire lugs were worn on a Kitchener strap. Both styles were in common use during the WWI period through to the end of the 1920s.
 
This watch is most likely from the 1927-28, as it has the triangluar MST logo (registered in 1927) while the case is not Roamer signed (in-house case production was in full swing by 1928), and this watch must fall between these two dates.
 
The watch features an enamal dial, red 12, cathederal hands and radium lume.
 
The second image shows the watch in as-found condition, when it was bought as part of a lot with a 1915 Waltham. The third image shows the condition of the hands and dial, with a temporary crystal fitted (old yellow crystals lead to corrosion of the hands). The subsequent photograpsh show the repaired movement (new 4th wheel pinion jewel, set lever screw, and mainspring), the new lume to the hands (the dial lume is original - note the old lume repair to the 7) and with the old and fragile (likely close to period correct) crocodile strap.
 
The final photos show the watch on a modern piliot style strap.