This bracelet is constructed from authentic WWII era coins.  The 1943 steel penny was minted due to copper shortages during the war, but was unpopular with the public due to its magnetic qualities causing jamming  in many vending machines. To solve that problem, in 1944 and 1945 the US mint recycled large brass shell casings, often brought back from naval gun ships, into the pennies on this bracelet.