This is Ledlenser's own 14500 lithium-ion rechargeable battery, a spare or replacement for compatible Ledlenser torches that use a single 14500 cell, such as the P5R and P5R Pro. A 14500 cell is the same size as an AA battery but delivers 3.7 V, so it gives much better performance in lights designed for it. This one has a capacity of 920 mAh and 3.404 Wh of energy, measures about 50 x 14 x 14 mm and weighs about 21 g. Keeping a charged spare means your torch is ready when the first battery runs flat. Only use it in lights designed for a 14500 lithium-ion cell; check your product manual or the existing battery before buying. Supplied as a single battery in Ledlenser packaging.