This machine uses one CR2032 battery and three LR44 batteries. These aren't the kind of batteries that the typical homeowner hangs around with. And the cost of replacing these batteries is higher than the cost of the device. Also, you need to disassemble the device, two small Phillips screws to replace the batteries. I currently have two digital meters that use two AAA batteries, with a convenient sliding door for removing and replacing the batteries, no tools required. And in many cases, AAA batteries are typical household items and are relatively inexpensive. I will be returning this unit and trying to find a unit that runs on AAA batteries.