This double-sided stainless steel jigger is a must-have for any well-appointed bar. One side measures a shot ~ 40 ml (1.35 fl oz.); turn over to measure ~ 20 ml (~0.675 fl oz.). Markings on both the inside and outside of the jigger for easy read. Each mark"s in increments of 10 ml. Pour and measure quickly. Andrew "the Alchemist", a bartending instructor in the Los Angeles area said "This jigger also happens to be functionally equivalent to 1-1/3 fl-oz. [39.63 ml.] x 2/3 fl-oz. [19.71 ml.]. This allows for making a drink in a 2:1 proportion and having the total volume of the liquor be 60 ml., or equivalent to 2 fl-oz. [59.14 ml.], which was total amount of "the jigger" as a unit of measure in American bars before prohibition." So, you all have fun being a mixologist! This bartending tool is food safe and easy-to-clean. Made of 18/8 stainless steel with quality craftsmanship. A perfect complement to our cocktail shaker or other barware, so combine shipping and save! Each jigger is shipped in a protective non-woven pouch-your assurance that you are receiving an authentic StainlessLUX product. One year limited warranty.