what batteries do airtags use

AirTags use a standard coin-shaped CR2032 lithium 3V battery. This type of battery is available at most electronic and drug stores. Apple warns that some batteries with a bitterant coating intended to discourage children from swallowing them may not work with AirTags, so it is recommended to find a brand known to be compatible. To replace the battery, press down on the polished stainless steel battery cover of the AirTag and rotate counterclockwise until the cover stops rotating. Remove the cover and battery, insert a new CR2032 lithium 3V coin battery with the positive side facing up, and replace the cover, making sure that the three tabs on the cover align with the three slots on the AirTag. Finally, rotate the cover clockwise until it stops.