The Firefly 2 Lithium-ion Battery is rechargeable and high-powered with a capacity of 770 mAH. This battery charges quickly, inside your Firefly 2 or outside, in as short as 45 minutes. Because this battery is more powerful than the older 750 mAH battery, it can help your Firefly 2 last longer. If you are someone who hates waiting for batteries to charge, it is recommended that you purchase spares of this product. The Firefly 2 is an Original Equipment Manufacturer (OEM) product and is the same as the original one that came with your device.