1 transmitter, 1 receiver and no batteries requiredA wireless doorbell requires no wires or batteries, protecting the environment and saving money. So you don't have to worry about changing batteries.Over 150m receiving rangeThis wireless doorbell has two receivers. Whether you're upstairs, in the yard, or by the back door, just place a receiver near you. The siren sound will successfully get your attention.IP44 waterproofWorks well in both wet and dry conditions and can be easily installed outdoors. It has an operating temperature range of -4F to 140F. So you don't have to worry about bad weather outdoors, such as rain, snow, scorching sun.LED indicators, multiple ring tones and volume1. 38 different ringtones to choose from;2. The volume is 0-110dB, adjustable in 3 levels (when the setting is 0dB, the visitor presses the button and the LED indicator light flashes).Specification:Working voltage: AC 100V-230V 50/60HzWorking frequency: 433.92MHzStandby power consumption: 0.25WMusic: 38 piecesVolume: 3 filesControllable volume: 50dB/1mReceiving distance: 150 meters (open space without obstacles)Receiver working temperature: -10C~+45CTransmitter operating temperature: -20C~+60CReceiver size: 66*50*55mmTransmitter size: 70*46*23mmThe transmitter does not need a battery, it generates electricity automatically by pressing