Nice ring.  The design looks to be from the 40's or so.  The ring falls on a US Mandrel between a US Size 11.5 and 11.75, which is a UK size W 1/2 and X. The face of the ring is 4mm north to south by all the way around. 

It is fully hallmarked, has been tested, and verified weighing in at 4.3 grams. There are no problems. This item is pre-owned and there will be ordinary and normal use marks. Comes from a clean, smoke-free home. 

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