Pretty sunshine of your life，welcome to my store!Description:Wireless door chime is great for retail store， shops， business， salons， front / back / side door， etc. Attach this infrared alarm anywhere you want and instantly know when someone crosses the beam. Infrared sensor detects motion and sends a signal to the receiver?Wireless installation， just place the sensor at the entrance?Receiver requires 2x AA batteries， transmitter requires 1x 9V battery (batteries not included)?Send audible chime sound， alerting you that somebody is approaching (Note: only one music type sound， no changing )?Transmitter Size (L x W x H): approx. 9*6*4.5cm?Receiver Size (L x W x H): approx. 9*6.5*2.5cm?Receiver Switch Setting: High / low volume / off?Material: Plastic?Color: WhitePackage Includes:?1x Transmitter?1x Receiver?2x Mounting accessories