1. No need to install batteries, just plug in the phone line and it can be used 2. Small and exquisite appearance, only 6cm wide, easy to place, does not take up space 3. Up to 90 decibels of sound, 50 meters of effective distance is more suitable for noisy places, big space or more rooms. 4.The volume of ringtone can not be adjusted, It is aloud to assure the calling can not be missed. If you want the ringtone can be adjusted and slight, This product is not suitable,please give up buying.
