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This is a standard pattern “trench watch”. Yours appears to be quite a high quality example; 15 jewels, and snailing decoration to the movement bridges. I don’t recognise the movement, but these would often be built at the shop with a chosen case (which may be English and silver) and your choice of movement.
The hour hand is repairable and will look like new when corrected. The enamel dial looks good.
Wash your hands after opening the watch as the lume on these watches has a high Radium content.
Great grandfather's watch, any ideas what it is? Case back was plain.