what kind of batteries do airtags use

Apple AirTags use a CR2032 lithium 3-volt coin battery. This type of battery is popular for its long-lasting lithium chemistry and ability to operate under extreme temperatures. When replacing the battery, it is best to use a CR2032 battery without a bitterant coating, as coated batteries might not work properly with the AirTag. The battery typically lasts about 12 to 18 months depending on usage.