Wireless Doorbell Home Wireless Self-powered Long-distance Doorbell feature: [No Battery Required,Self Power Door Bell] -No need extra battery for the Transmitter,press and transform kinetic energy into electric energy.then the transmitter release signal to active the door bell receiver.Save the energy to change battery and environment friendly. [Strong Signal] -Over 150 meters effective range and strong ability to penetrate wall,available for big house. [IP68 Waterproof] -Rainy days can be used ,safe &durable. [One Transmitter can Pair with Several Receiver] -no need worry miss the door bell ring of every important visitor [38 Kinds Ring Tons&4 Level Volume Adjustable] -in total 38 kinds ring tons available,4 level volume adjustable, including mute.Fully satisfy your different requirement in different scene and room. [Easy to Install] -Transmitter button can be paste on the door via double side tape, or screw on the wall with the bottom plate. And the receiver bell can be plug in any home outlets. SPECIFICATION - Operation Voltage:100-230V - Power Consumption: 0.25W - Wireless Frequency: 433MHz - Ringtone Volume: ?50db/m - Receiver Size:95*54*68mm - Transmitter Size: 80*50*28mm - Transmitter Power Type: Self Power