Energizer A544 Battery provides reliable power to your important electronics. This small battery delivers big power and is compatible with a variety of devices, including your bluetooth headset and medical devices like glucose monitors. Reach for this alkaline battery when you need a replacement camera battery or a battery for your dog's LED collar. These miniature alkaline batteries contain zero mercury to responsibly power your gadgets while minimizing environmental impact. Count on Energizer, the #1 brand of specialty batteries, to deliver dependable, long lasting power to your devices.