Keep your devices powered with ease when using Duracell's Ultra Power Alkaline 9V Battery. Batteries in the Duracell Ultra Power series come with a Powercheck. This is an integrated tester that lets you know how much power is left in the battery, taking the guess work out of how much power you have left. The Duracell Ultra Power Alkaline 9V Battery provides up to 80% more power compared to other batteries. With Duralock 10 years power preserve, keep our devices powered for longer with the Duracell Ultra Power Alkaline 9V Battery.