Duracell Silver Oxide Coin Button batteries have a 3-year guarantee in storage with Duralock Power Preserve Technology, so you can be confident these batteries will be ready when you need them. They offer reliable, long-lasting power for your specialty devices such as watches, calculators and medical devices. Up to a 3-year guarantee in storage with Duralock Power Preserve Technology #1 trusted brand of pharmacists and medical & office professionals Duracell Silver Oxide Coin Button batteries contain 0% mercury; These silver oxide coin button batteries are great for watches, calculators and medical devices