Cocktail shakers became the focus of American industrial designers about 1920. World War I was over and American wanted to party--but Prohibition sent drinking out of the public eye and into speakeasies and living rooms. So, of course, fancy mixed drinks with exotic names and flavors became symbols of sophistication and style.
Silver makers saw a market and started producing not just shakers, but complete cocktail sets. By the 1930s, other companies were making shakers and sets from less expensive materials, such as glass, chrome, brass, copper, and Bakelite. Often, cocktail shakers have detachable stoppers and stirring spoons.
Kovel, Ralph, and Terry Kovel. "Shaking Fancy Cocktails." KOVELS (On Antiques and Collectibles) JUNE 2004: 111.