The UltraFire 10440 rechargeable 3.6V battery adopts universal standards most of them suitable for cameras toys and many other electronic devices. Except that it features extensively long working life and high efficiency great for use. The durable and reliable battery is compact and rechargeable so you can carry it anywhere anytime convenient to use. - Ideal upgraded power source for BRYNE flashlights - Charge using BUKTA convenient AC charger - Ultra-high capacity and premium built quality - Note : Professional users have tested these batteries' capacity to be 305mAh each and Ultrafire is overrating them as 500mAh. Please read the "measured capacity" forum post below.