For power you can rely on, choose Energizer Max D batteries. They feature Power Seal Technology, which holds power for up to 7 years while in storage, providing long life for the devices you use every day.Always keep extra batteries on hand. World's 1st Zero Mercury D Alkaline Battery. Energizer is a leader in the industry in powering people's lives responsibly. Up to 7 years shelf life. Package of four batteries.