The new SEC-MQN064N 4-AA eneloop with AC charger pack utilizes SANYO's advanced rechargeable battery technology allowing them to last longer than ever before! They provide excellent performance-to-cost advantages over both conventional alkaline and other rechargeable batteries. Unlike disposable batteries which can only be used only once and are wasteful to the environment, the new eneloop batteries can be recharged up to 1500 times. They also maintain 75% of their charge up to 3 years when not in use. The come pre-charged and can be used immediately out of the pack, eneloop batteries deliver reliable battery performance when you need it the most!