Each of these GP Recyko AA 2100mAh Rechargeable Batteries is a NiMH rechargeable AA battery that's high-performing, long-lasting and good for the planet. This battery pack of four is equivalent to thousands of single-use batteries.. Pre-charged and ready to use, it can stay up to 80% charged after 12 months thanks to its low self-discharge rate. With an operating temperature ranging from -20°C to +50°C, it delivers reliable performance even in extreme environments.. Sustainable? Very. The battery is certified as made of more than 10% recycled materials (in general, batteries with recycled materials reduce energy usage, consumption of fresh raw materials and pollution). 94%+ of the entire battery pack including the box can also be recycled.