A gin fizz is the best-known cocktail in the fizz family. A gin fizz contains gin, lemon juice, sugar, and carbonated water, served in a tumbler with two ice cubes.[2] The drink is similar to a Tom Collins, with a possible distinction being a Tom Collins historically used "Old Tom Gin" (a slightly sweeter precursor to London Dry Gin), whereas the kind of gin historically used in a gin fizz is unknown.[3]