ECO Recharge is environment-friendly recyclable and reusable batteries for your everyday needs. One single battery cell can compare to 500 of the traditional disposable alkaline batteries and those can be eliminated from going to landfills. In a 4-pack version, you will prevent 2000 disposable batteries going to landfill which will also save you from buying those 2000 alkaline disposable batteries. These batteries are different as they have a built-in recharge control and it will never overcharge itself. It comes with a USB cable to perform recharge. It works the same way all the AA and AAA batteries work. When the power is out, instead of disposing of the batteries you will just recharge and reuse.