new wireless doorbell USB doorbell for you charming prices

Description

benefits and features of usb doorbell
wireless 
battery-free, wireless 
DC powered receiver 
usb plug 
remote control
*8 polyphony ring tones 
stable performance  

tech intro. of usb doorbell
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 willconvert 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.