Ultra Power is Duracell's most powerful alkaline battery Ideal for Toys Games and stereos Comes with PowerCheck, an integrated tester that lets you know how much power is left in your battery Up to 40% more power in high drain devices (vs. Duracell Plus AA, results vary by device) 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-p