As someone who’s spent the better part of his life mixing drinks, one of the clearest demarcations I find between a fantastic drink and a merely mediocre drink is accurate measuring. Visit any cocktail bar known for the quality and inventiveness of their drinks and you will see everyone behind the bar relying on jiggers, vessels specifically designed to measure out precise — and small — quantities of liquid. A set of good jiggers is an absolute must for any seasoned bartender, and they are doubly essential for the amateur drink-slinger making cocktails at home.