One For Three Home Wireless Doorbell AC Digital New Arrival New Self-powered Waterproof Wireless Doorbell No Battery Need US EU UK Plug LED Doorbell 150M Remote Home 60 Ring Calling Bell Wireless Doorbell No Need Battery AC100-240V Battery-free wireless doorbell no battery need and no wire. It uses unique energy harvesting technology and ultra-low-power wireless technology with worldwide patents pending.Help you to save your money and power. Specification Color: White/Black ( ABS) Plug: EU/US/UK Plug-in( US+ AU adapter) Water Proof: Yes Power: AC100-240V(receiver), Self-powered(push button) Working range:150m in open area RF Frequency: 433MHZ Melody: 60PCS Volume:5 files Feature:Self powered(No need battery) Note: Press the pressure is slightly larger than the traditional doorbell, to ensure adequate power generation How to pair signals 1.Pairing method:Press and hold the volume button on the receiver for about 5 seconds (the light is on), release the volume button, then press the transmitter immediately, the signal is successfully paired.