Eneloop +

Eneloop is a brand developed by Sanyo encompassing rechargeable batteries and associated devices, introduced to the market in November 2005. The batteries are low self-discharge NiMH, which lose their charge much more slowly than traditional NiMH batteries; 10% in the first year, compared to about 20% on the first day and 1–4% on every successive day. The Eneloop batteries are sold pre-charged and can be used immediately, while traditional NiMH batteries lose their charge so quickly that this isn't feasible. Due to the number of alkaline batteries they can replace during their lifecycle, they are marketed as being eco-friendly when used appropriately.