Original American Soda King brand Carbon dioxide capsule/charger key, believed to have been manufactured in the late 40's to early 50's, and designed to fit the early versions of the glass and metal bodied soda syphons from that period.   These syphons either have a heavy chrome plated pewter head, a chrome plated bakelite plastic head or a black bakelite head which features a metal threaded part onto which the key screws.   This item does not fit the much later totally bakelite heads  which took the hollow cup shaped charger holders.   Produced in a light-weight die-cast zinc alloy and designed to fit the C (8 gram) sized CO2 capsule, which remains widely available to this day.