Features: 1.Premium Material: Made of premium ABS, the wireless doorbell is exquisite, durable, reliable, practical and has a long service life, it is convenient to put anywhere. 2.2 Receivers: The ABS wireless doorbell has 2 receivers, which can be used in different rooms or set separate corresponding ringtones. 38 musical ringtones with good sound quality and high volume can be chosen as you wish. 3.Self Generating: The black wireless calling bell is self powered, no need to worry about the battery, built in power energy generation modules, no battery and no wiring. 4.150m Range: The signal of self generating doorbell can penetrate 3 to 4 walls and up to 150 meters in open areas, the doorbell is waterproof and rainproof. 5.Suitable: The 150m wireless doorbell is suitable for family, villa, hotel and factory, senior citizen, patient, pregnant can call with one key. Specification: Item Type: Self Powered Wireless Doorbell Material: ABS Weight: 165g/5.82oz Color: Black Suitable: For Family, Villa, Hotel, Factory, For Senior Citizen, Patient, Pregnant to One Key Call Doorbell: Power Supply: Self Generating Transmission Distance: 150m/164.04yd Without Occlusion Radio Frequency: 433MHz Receiver: Power Supply: AC 110-230V Ringtone: 38(4 Levels Adjustable) Ringtone Volume: 50db/1m PackageList: 1 x Wireless Doorbell 2 x Receiver 1 x Double Sided Tape 1 x Use Manual Note: Please supply power according to the voltage in use, use other voltages may cause fire and damage!