What is the device's power source? Updated October 30, 2024 20:01 Kardia 12L uses two AAA alkaline batteries, which can be replaced. It does not use wall power. Kardia 12L uses two AAA alkaline batteries, which can be replaced. It does not use wall power. Related articles How do I record Blood Pressure in the Kardia app? Can you download recordings and share them from the app? What is the lifetime of the device? What can I use to clean the device?