Military marking question

I have a friend who has a question regarding the markings on the case back of his 7-jewel Waltham. I have no clue regarding military stuff. I’d be grateful if someone could decipher these marks for me. Thanks for any help offered.

Thanks @omegastar for that. Is there anything that might indicate which military? The arrow mean anything? @UncleBuck , your link leads to an answer in a different thread.

I think the arrow is a pheon, related to the British military.

Thanks everyone. That helps.

Without wishing to be pedantic, I'll throw another variation into the ring.

GSTP refers to General Service Trade Pattern.

This was applied to watches purchased by various British Commonwealth military organisations. Due to the shortage of watches that met military specifications (used for navigation etc.), watches for general duties were quickly purchased from the civilian watch market (the trade), thus "Trade Pattern".

Or does it? There is also another possibility.

GSTP refers to General Service Temporary Pattern.

For much of the same reasons as above, watches that did not meet "milspec", but were needed for general time keeping, were a "Temporary Pattern" and not related to a British Military Standard.

This is another of those mysteries that has endured since the watches were issued, and until some dusty archive yields up its documents, the actual meaning of GSTP will always be a subject of polite reasoned discussion among watch collectors.

Regarding the Broad Arrow (pheon) symbol.

This has been used for hundreds of years to mark items owned by the British military and is/was also by British Commonwealth nations, e.g. Australia, New Zealand, Canada, India and others.

It could be considered a "military hallmark" as it's a criminal offence to mark items without permission from the DoD, in the same way that it's an offence to use fake hallmarks.

Thanks to @JimInOz for that. My friend is from England, and served as guard at Buckingham Palace, 50 or so years ago. He will be interested.