Original Sparklets brand Carbon dioxide capsule/charger key, manufactured in the late 20's to early 30's, and designed to fit the Sparklets Type C glass bodied soda syphons (although this key will fit any Sparklets syphon from the 1920's through to the 1980's).  Produced in a heavy-weight die-cast zinc alloy and designed to fit the C (8 gram) sized CO2 capsule, which remains widely available to this day.  This item is rare in that it still retains the vast majority of its original black paint coating, indicating this was probably supplied with a basic Type C model.