Creative Technology， No Battery， Self-powered(No need battery)， more convenient for user， better for environmentWireless doorbell， signal can pass through doors， walls， floors. Remote distance is up to 100m outdoor， 30m indoor36 selectable ringtones is good for your ears and keep good mood， the volume is high enough to cover your houseLED indicator on both transmitter and receiver， transmitter service life is up to 200000 times pressingPackage includes: 1 x Doorbell Transmitter with 3M adhesive tape (button); 1 x Doorbell ReceiverParameters:Doorbell Type: WirelessColor: WhiteReceiver: AC PlugTransmitter: Battery-less， Self-powered(No need battery)Music: 36 melodies musicWorking Frequency: 433.92 MHzVolume: 4 levels adjustable.(max 105 dB)Transmitter button working environment: -40 C - 60 CWaterproof: IPX7Size: Diameter 67mm， Thickness 20mmFeatures:Creative Technology， Battery-less， Self-powered(No need battery)， more convenient for user， better for environment.Wireless doorbell， signal can pass through doors， walls， floors. Remote distanceis up to 100m outdoor， 30m indoor.Transmitter service life is up to 200000 times pressing.36 selectable ringtones is good for your ears and keep good mood， the volume is high enough to cover your house.LED indicator on both transmitter and receiver.Package includes:1 x Doorbell Transmitter with 3M adhesive tape (button)1 x Doorbell Receiver1 x Backup 3M adhesive tape