Features:1. Long-distance signal transmission, up to 300 meters straight line distance in open area(Note: The actual receiving signal varies depending on the environment, and the signal is different due to different obstacles)2. 45 chimes with 4 level adjustable volume. The receiver has an indicator light. A flashing light will remind you when the doorbell rings3. Power supply mode: The transmitter has built-in battery, and the receiver plug in socket.4. The receiver adopts intelligent power management technology with low power consumption and can be plugged in for a long time. Safe and secure. The transmitter can be installed in an outdoor environment, rainproof, waterproof and sunproof.5. Scope of application: Home, commercial, residential areas, office buildings, hospitals, restaurants, factories and other places6. Easy installation: The transmitter can be fixed with screws or double-sided tape. When using double-sided tape, please press for 30 seconds and then let go, it is not easy to fall off.Notice:1. Actual color may be slightly different from the image due to different monitor and light effect. Please allow 1-3cm deviation due to manual measurement.Specification:Receiver doorbell:Power supply: AC, plug-inAmbient temperature: -20-55degCTransmission distance: 300 meters straight line open distanceRingtones: 45 polyphonic musicVolume: 0-110dB(4-level volume adjustable)Size: 85x65x23mmWorking frequency: 433.92MHZTransmitter doorbell:Power supply: 12V 23A battery (included)Ambient temperature: -20-65degCWaterproof level: IP44Size: 77*50*16mm