This is a blister pack of 4 Eneloop AA Ni-MH Batteries from Sanyo. These batteries are superior to traditional alkaline AA batteries since they are rechargeable and will retain their charge over a 3-year span. They come pre-charged out of the pack and can be recharged approximately up to 1500x. They are also a cost-effective and environmentally friendly way to use batteries since they can be re-used over and over without having to toss them away.