Energizer A23 Batteries provide reliable power to your important gadgets. These mini batteries are compatible with a variety of devices, including your keyless entry system, bluetooth headsets and home security systems. Reach for these specialty batteries when you need replacement camera batteries or a new garage door opener battery. Miniature alkaline Energizer batteries contain zero mercury to reduce environmental impact. Count on Energizer, the #1 brand of specialty batteries, to deliver dependable, long lasting power to your devices.