Lithium-polymer chemistry; 3.82V of power; up to 6-month shelf life

Stay connected to apps, text alerts and fitness tracking feedback when you use this UltraLast smartwatch replacement battery. The convenient design works with select Apple smartwatches for dependable operation, and the rechargeable design makes it easy to keep your device powered up. This UltraLast smartwatch replacement battery slides effortlessly into place for hassle-free installation.