Duracell High Power Lithium CR2 batteries are made with high-purity lithium for long lasting power guaranteed. Results may vary by device and usage patterns) for your smart home devices (sensors, keyless locks, smoke detectors), photo flash, flashlights, bike accessories and electronic dog collars. They have up to 10 years of in-storage guarantee with Duralock Power Preserve technology so you can be confident these lithium batteries will be ready when you need them.