123 or CR123 batteries are the most common size of specialty battery. They're often used in flashlights, digital cameras, and other small electronic devices. They have a nominal diameter of 17 mm. Disposable specialty batteries provide increased capacity to handle spikes in power demand. They're used in high-drain devices such as digital cameras, Wi-Fi-enabled equipment, tactical flashlights, occupancy sensors, defibrillators, microphones, and faucet sensors. These batteries are typically cylindrical and look similar to standard disposable batteries while providing more power for demanding applications. They can be discarded when their charge runs out.