You need this shopkeeper helper ★ Welcome device (sensor doorbell), greet customers in a timely manner to avoid the problem of unenthusiastic waiters or dry mouth after greeting. ★You can also remind the clerk when few people are taking a nap. ★The sensor and the host are separated, and the host is detachable and can be turned off directly when there are many people. ★The host has a long receiving distance and the application areas are greatly expanded. It can be used in stores, companies, schools, families, etc. 5 functions: Home/Doorbell/Alarm/Light/Night light 5 welcome sounds, 36 doorbell music AA battery + USB power supply, power off memory 280 meters long distance transmission 113dB