Sorting thru my pennies and took out all of the 1943 steel cents.  The 1943 steel cents were struck in steel due to wartime shortages of copper.  The Philadelphia, Denver, and San Fransisco mints all produced the 1943 cent in steel.  This unique composition consisted of low-grade steel coated with zinc; instead of the previously 95%-copper-based bronze composition.  The 1943 cent is known as the "wartime cent", "steel war penny", and "steelie".