Specification: Item Type: Wireless Doorbell Material: ABS Application: Home, Shop, Office, Doorbell or Pager Transmitter: Power Source: Self-generating Ambient Temperature: -20-+60 Transmission Distance: Open area > 150M RF Frequency: 433MHz Receiver: Power Supply: AC110-240V 50 /60Hz Power Consumption: 0.25 W Ringtone: 58 Ringtone Volume: 90 dB Ambient Temperature: -10-+45 4-Level Volume Adjustment: The doorbell features 58 melodies to choose from and 4-level adjustable volume, louder than 90dB, meeting your various needs. Adjust the volume to suit individual preferences. Long Range Wireless Doorbell: The transmission signal for this wireless doorbell reaches up to 150m in an open area, making it suitable for various scenarios such as apartments, houses, offices, and more. Multifunctional: Not just a doorbell, but also a pager, suitable for babies sleeping alone, the elderly, and pregnant women. This wireless doorbell has IP44 sun and water protection, withstanding harsh weather conditions. Operating temperature is -10-+45. Easy to Install: Installation is simple. Just plug the receiver into a power source and attach the transmitter to the wall with the included sticker. No wiring or batteries required.