Get dependable, long-lasting power from D Coppertop batteries. These batteries have been engineered to deliver the power you need for all your common devices. They are recommended for use in toys, remote controls, flashlights, calculators, clocks, radios and more. Duralock Power Preserve Technology ensures they are dependable after 10 years of storage.Get dependable, long-lasting power from D Coppertop batteries. These batteries have been engineered to deliver the power you need for all your common devices. They are recommended for use in toys, remote controls, flashlights, calculators, clocks, radios and more. Duralock Power Preserve Technology ensures they are dependable after 10 years of storage.