Introduced in May, 1929, Silverice was, in the beginning, sold exclusively through Mary Ryan of 5th Avenue, New York and cost $5 for a box of six. The metal balls contain liquid. Put them in the freezer and, when frozen, place in glass. Unlike ice, Silverice does not melt & dilute cocktail. I'm not sure what liquid is inside Silverice, so I'd be a bit leery of using them. But the Deco design box and these 90 year old cocktail items deserve a special place in your Cocktail Shaker collection.