MecArmy M104 10440 Lithium Ion Button Top Battery320 mAh 3.7VThe MecArmy M104 10440 Rechargeable Battery is a powerful Lithium Ion cell designed for use in LED flashlights and other high performance devices. Roughly the same size as a AAA battery, this impressive cell delivers 3.7V of current, over twice the power of an alkaline AAA and 3 times the power of a NiMH AAA. This cell is perfect for high drain devices that need a bit more juice than typical alkaline and Nickel-based cells can offer. The long-lasting cell can be recharged hundreds of times without seeing any decrease in its capacity, giving you years of use!Specifications: Battery Size: 10440 Battery Chemistry: Lithium Ion (Li-Ion) Nominal Voltage: 3.7V Nominal Capacity: 320 mAh Shelf Life: 10 Years Dimensions: Length - 1.83" (46.5 mm) Diameter - 0.41" (10.4 mm) Weight: 0.35 oz. (10 g) NOTE: This battery is NOT a replacement for Alkaline, NiMH, or Lithium Primary AAA batteries. Due to its significantly higher voltage, using this cell in devices designed for the aforementioned chemistries can damage the device.