PLEXXA(TM) 32 Melody Welcome Alarm Wireless Door Bell Wireless IR Infrared Warning Monitor Doorbell Alarm Alert Chime Motion Sensor Detector for Shop Home Office etc (Dark blue) 32 pieces of beautiful music available Host built-in speaker, alarm loudness of 75-95 dB Strong sensitivity, non-mislead and anti-interference technology Advanced microcomputer technology and automatic human sensitivity alarm doorbell Suitable for home, office, shop, store, conservatory, garage, sectional building etc