The Red Ensign or "Red Duster" is a flag that originated in the early 17th century as a British ensign flown by the Royal Navy and later specifically by British merchantmen

with a battery life indicator

It’s just as waterproof

Flying Scotsman and Mallard steaming out of King's Cross

Internal dimensions are:

Limit Sports Watch, black/white BLACKTOTDAY The Red Ensign or "RedThe bright, oversized numerals, luminous hands, and backlight function ensure this sports watch can read easily at a glance. At 48mm diameter the case is large, but the watch remains incredibly lightweight at just 55g. 100m water resistant. Gift boxed.