RELIABLE DOORBELL ALARMS: M5 wireless doorbell motion sensor uses advanced infrared sensing technology. Built-in speaker and blue flashing light are suitable for the front door of office, store, restaurant, etc. with voice sound/greeting; for the front door of house, shed, etc. with alarm sound. When activated, the sound will be sent out quickly from this small door alarm buzzer. SMART MODE: The wireless motion sensor with doorbell is built in three alarm/music/voice modes that can be easily set up according to your needs, the wireless doorbell alarm sound continues for 15 seconds in alarm mode, 32 songs available for you to choose in music mode, and 4 volume levels adjusted for you. And there are also voice prompts like "dingdong", "Welcome" and "Hello" in voice mode. EASY TO INSTALL: The M5 wireless alarm doorbell is equipped with 2 screws and double-sided adhesive tape for installation according to your preference. The horizontal detection angle of the alarm sensor is 110° and the