Aigostar Wireless Doorbell, Self-Powered Door Bells 1 Receiver\nProduct Details\n--Self-Powered Door Bell: Are you fed of of buying batteries for your old door bell? Aigostar self-powered door bell use the pressure from your finger pushing the button to generates electrical power itself and sends a stable signal to receiver, without the need for batteries. This is very cleverly designed, if you care to have less battery waste in your environment then this is for you.\n--36 Ringtones & 3-Level Volume: Aigostar doorbell wireless has 35 different CD-quality chime options, 3 levels of adjustable volume from 25dB to 85dB. The sound is clear and loud enough for most. The memory function for sound and chime selection allows you don\u2019t need to set up again even after a power failure.\n--Broad Range Wireless Door Bell : The cordless doorbell features up to 150m/500ft wireless range, the chime can be heard throughout the house, ensures you won't miss a visitor or delivery, even if you .