Just needs you to press a built-in button called worm gear plane generator to produce power.

Energy harvesting technology, the new wireless bell requires a very tiny pressure only 350g.

Main features:

1.  Stylish modern design fits into any home and office.

2.  52 ringtones(16 chord)to choose from and 4 steps volume control(25~110dB).

3.  Simple to use and easy-to-install without the hassle of running any wires.

4.  With up to 300m operating range in open space,100m audible range.

5.  IP55/IP44 waterproof transmitter

6.  Eye-catching backlight flashes when someone pushes the doorbell.

7.  Different quantity of push unit(transmitter) and chime unit(receiver) are free to pair together.

8.  If paired multiple push units in one system,the chime can be set to different for each push unit.

9.  Using learning code to prevent interference from other wireless transmitters.

10. Easy to choose your change and select your favorite ringtone with forward and backward button.

11. Automatically save selected ringtone after power off.

12. Approved with CE,FCC,RoHS certification.

Specification:

No battery required wireless doorbell button

Battery in Transmitter: 12V 23A Alkaline Battery

Voltage of Plug-In Smart Receiver: AC 110V ~ AC 220V 50Hz/60Hz

Power Consumption (Transmitter): < 10mW

Wireless Range: 600 ft in Open Air; 100~300 ft with doors and walls

Selectable Ring Tone: 52 Options

Volume Range: 4 Levels (up to 110 dB)

Expandable to Multiple Smart Receiver or Transmitter: Up to 50

Working Frequency: 433.92 MHz±280KHz

Working Temperature: -30℃~70℃

Plug type:AU,US,EU,UK optional