Audrey Sanders created one of the most famous iterations of the equal parts Martini at Pegu Club. Featured in his new book The Martini Cocktail, Robert Simonson explains, "for orange bitters, she used a house mix of Regan’s and Fee Brothers—the only orange bitters brands widely available. The combination became known as Feegan’s. Saunders is adamant that, since the drink is a mere three ounces in volume, only one dash of Feegan’s is needed."