Massive Extra Performance and The UK's Lowest Price - Extra Value 4 Pack of "the Worlds longest lasting AA battery", which lasts up to 7 times longer than even the very powerful alkalines. User benefits include around half the weight of alkaline batteries plus improved operating temperature of down to -20 centigrade. A particularly good product where carrying replacement batteries may be a problem or when battery power is required for long duration without inconvenient battery change interruption especially in digital cameras. A very popular product with enthusiast and professional photographers around the world, especially in digital cameras, motor drive and flash units. Also has a 10 year shelf storage life so no worries about buying a few extra packs to keep as spares !