The new SEC-NCSD2AAN eneloop "D" spacer kit with 2 AA batteries 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 1,500 times. They come pre-charged, can be used immediately out of the pack and maintain 75% of their charge for up to 3 years when not in use. Eneloop batteries deliver reliable battery performance when you need it the most!