Upgrade your device with Duracell’s most groundbreaking innovation yet. Duracell Optimum batteries have a proprietary cathode system that can deliver extra power in some devices, or extra life in other devices, vs Coppertop AA and AAA, in a wide range of devices. Optimum Batteries are packaged in a slider pack with a resealable storage tray, that provides a more organized way to store your batteries. Battery Type: Alkaline; Battery Size: AAA; For Use With: Everyday Electronic Devices; Voltage: 1.5 V.