One pack of Philips Power Alkaline Batteries, 9V: Alkaline technology is perfect for gadgets that use a lot of energy. Alkaline batteries outperform typical zinc carbon batteries by a factor of 6. The battery can be used for up to five years without losing its quality. Philips alkaline batteries have no lead, mercury, or cadmium. Type of battery: 9V/6LR61 9 V is the alkaline battery voltage. Keep them running.