Size 6.5. Steel or some kind of nickel alloy. Possibly made by a serviceman out of steel (industrial object) for a sweetheart or wife back home, but it looks more to me like it was commercially made during wartime (WW2.) We know it's a wartime ring because silver (along with platinum) was reserved for military use and it was not exactly forbidden, but definitely unpatriotic to buy and wear jewelry made of those metals at that time.