Thank you for viewing. This is a battery-powered wireless chime. (Although it says battery-powered, the batteries are not included, but a button battery is included.) You can install the transmitter in a place where you want to call someone, and call them even when you're away. It has been stored unopened, so I am offering it for sale. I'm not sure when it was purchased, but I think it's been a few years since I bought it. Thank you for your understanding.