Motion Detector with Sound Alarm Security Alarm for Door/Entrance Gate/Home and Shop/Office M5 Wireless Doorbell Reliable Doorbell Alarm: The M5 Wireless Doorbell Motion Detector uses advanced infrared detection technology. Its built-in speaker and blue flashing light are suitable for front doors of offices, shops, restaurants, and more, with a voice/greeting function. It can also be used at front doors of houses, sheds, and more, with an alarm sound. Once activated, this small door alarm buzzer will sound quickly. Smart Mode: The wireless motion detector with doorbell has three built-in alarm/music/voice modes, easily adjustable to suit your needs. In alarm mode, the wireless doorbell's alarm lasts 15 seconds. In music mode, you can choose from 32 songs with four adjustable volume levels. Voice prompts such as "Ding Dong," "Welcome," and "Hello" are also available in voice mode. Easy Installation: The M5 Wireless Alarm Doorbell comes with two screws and double-sided tape for installation according to your preference. The alarm detector has a horizontal detection angle of 110° and a vertical detection angle of 15°. You can mount the wireless alarm doorbell on your front or back door. When activated, the home alarm doorbell's motion detector notifies you of the presence of a visitor or intruder. <br />Dual Power Supply: The wall-mounted presence detector uses an external DC5V power adapter (not included) and three built-in AAA batteries (not included) to ensure ample power. The low-battery reminder function allows you to replace batteries promptly without worrying about power outages and missed alerts. </li> </ul>