The shaker is a bar utensil used for the preparation of cocktails. It is used to mix the cocktail ingredients by shaking them vigorously in the shaker.
The shaker is made of three parts: a large container at the bottom, often made of metal, a top part that allows you to close the shaker to shake it, often perforated to filter the cocktail, and a glass inside that contains the cocktail ingredients.
Boston Shaker: the Boston shaker is made of two parts: a large metal cup made of stainless steel and a very thick glass. This is the most appreciated shaker of professionals because it is more airtight, quicker to handle and quicker to rinse. The cup has a larger opening diameter than the glass, so that the glass fits into it. The mixing glass is designed to withstand heat and physical shocks caused by the use of ice in cocktail preparation.