Duracell Ultra Power provides up to 40% more power vs Duracell Plus. The premium alkaline battery that offers a premium performance in all devices. Every Ultra battery has a Powercheck tester, so you always know how much energy is left inside. It is specifically designed to be the most powerful Duracell alkaline in all devices.In high drain devices vs. Duracell Plus AA/AAA. Results vary by device.Duracell has been powering the needs of people around the world for more than 40 years. Its products serve as the heart of devices that keep people connected, protect their families, entertain them and simplify their increasingly mobile lifestyles. Duracell is the world's leading manufacturer of high-performance alkaline batteries and a recognised leader in advanced battery technologies including lithium, manganese dioxide and zinc air batteries as well as nickel metal hydride rechargeable batteries. Duracell's products are designed to give you maximum power. Whatever your power needs, it will last longer with Duracell.