Technical Parameters: 1. Receiver Rated voltage: AC(110-240V/50-60HZ) 2. Receiver standby power: <0.5 W 3. Sensor: DC 3V 4. Sensor operating power: <10 mw 5. Receiver induction angle: 120° 6. Receiver induction distance: 0-3 m 7. Sensor battery model: CR2450 8. Volume: 25-85dB 9. Working frequency: 433 MHz Others: 1. Receiver must plug into the socket 2. Self-learning code function operation 3. Receiver with breakpoint memory function, though powered off, the sound and the volume remain the same when power on. Tips: Please tear up the transmitter battery insulation sheet before use.