Easy open aluminum ends for beer cans must meet the ultimate consumer's, the brewer's, and the can manufacturer's requirements. This article details these needs and explains how design parameters have been determined and how end unit designs have evolved to meet these requirements. A detailed explanation of specific terms associated with easy open ends is presented. A step-by-step history of Continental Can Company’s development of the easy open aluminum end is discussed together with the reasons which have dictated design changes. A brief presentation of the impact of easy open ends on the beer can market and a brief look at what may be expected in the future outlined.