SMITHS MILITARY DELUXE ISSUE A409 PATTERN DENNISON CASED WRISTWATCH 1953 bwc case 19mm and 20 regular non

19mm and 20 regular non OE  black are currently a 549 not a 519

It looks like a b c etc prefix were all in the same year of production

You could always opt for a leather 16mm strap to be fitted and keep the bracelet spare

straight one piece click and click spring combined

and is an S

SMITHS MILITARY DELUXE ISSUE A409 PATTERN DENNISON CASED WRISTWATCH 1953 bwc case 19mm and 20 regular nonModel A409 Everest pattern Smiths Deluxe. Thirteen A409's were supplied by Smiths to members of the famous Everest expedition. This particular watch has been adopted for use by Pakistan forces and carries the appropriate engraving on the back. This is the version with the gilt baton hands. Excellent investment if you want the correct model that went up Everest. 33. 5 mm Dennison Aquatite signed case. Th thickness is approximately 10. 5mm. Excellent 12