Easy, Fast, Wire Free Installation: Infrared sensor detects motion and sends a signal to the receiver | The portable wireless plug-in receiver plugs into any standard outlet. | Alerting business owner or home owner with wireless doorbell. The ability to sense motion through the front or back door. Portable design to easily install in homes, office, work, retail store, or utilize it for mailbox, garage, driveway or other. | Ideal for front doors, window frames, driveways, walking paths, and anywhere in your home you want to be alerted to motion. Also great to alert business owners that are working in the back, or out of sight, to customers entering their store. | Package:1 pc Transmitter and Receiver(2 AA batteries not included)