battery-free wireless doorbell

Description

tech intro
Battery-free wireless doorbell requires no battery and no wire. It uses the unique energy harvesting technology and ultra low-power wireless technology with worldwide patents pending.
When users press the button, energy converting module inside will convert the mechanical energy into electrical energy. The wireless module of the button will send signals to the receiver, which will receive signals and play music.

benefits and features of wireless doorbell 

1. Self powered button. 
  It requires no batteries and other external power.
2. Wireless.
  You can use it anywhere as you like.
3. Waterproof transmitter. 
  Soak it in the water for four month, it still works well.
4. Inflame retarding receiver.
  Enlarge the safety of your house.
5. *8 polyphony ring tones in the receiver. 
  More choice, more happiness.
6. 100m long range distance in open area.
  Powerful signal transmission.
7. Endure low and high temperature.
  It can work even in a sever environment.
8. **3MHz .
  It has stable performance. 

specification