What is Jiiger
A jigger is a bartending tool used to measure liquor, which is typically then poured into a cocktail shaker. It is named for the unit of liquid it typically measures, a jigger or shot, which measures 1 1⁄2 US fluid ounces (44 ml). However, bar jiggers come in other sizes and may not actually measure a fluid jigger.
A traditional style of jigger is made of stainless steel with two unequal sized opposing cones in an hourglass shape on the end of a rod. Typically, one cone measures a regulation single shot, and the other some fraction or multiple – with the actual sizes depending on local laws and customs.
A small shot glass specifically marketed for kitchen use is graduated in units such as ounce and half ounce, teaspoons, tablespoons or possibly millilitres. They are useful for recipes that call for multiples of a smaller unit (e.g. several teaspoons), allowing the dispensing of the amount in a single measure.