Feature: 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 OcclusionRadio Frequency: 433MHz Receiver: Power Supply: AC 110-230V Ringtone: 38(4 Levels Adjustable) Ringtone Volume: ≥50db/1m. Package List: 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!