Feature:1. Self Generating Doorbell: When you press your finger, the kinetic energy is converted into electric energy, free of wiring, no battery.2. Adjustable Ringtones: 38 ringtones, includes classic doorbell tones and music tones, and 4 level adjustable volumeto meet your personalized needs.3. Long Range: The wireless doorbell signal has strong penetration, can penetrate 34 walls, and the longest transmission distance in open areas can reach 200 meters.4. Weatherproof: The wireless doorbell is made of ABS material, which is resistant to high and low temperature, waterproof, and effectively prolongs the service life.5. Wide Application: Doorbells are widely used, can be used in homes, villas, hotels, factories, as well as the elderly, patients, pregnant women, etc., one click call to protect the safety of family members.Specification:Item Type: Wireless Doorbell SetMaterial: ABSDoorbellPower Source: Self generatedTransmission Distance: Open Space: Approx. 200m/656.17ft; Indoor: Approx. 50m/164.04ftRF Frequency: 433MHzReceiverPower Supply: AC110-240VRingtones: 38 (4 level adjustable)Ringtone Volume: 50dB/1mUses: Can be used in homes, villas, hotels, factories, the elderly, patients, pregnant women, one key calling..Package List:1 x Doorbell2 x Receiver1 x StickerNote:Please supply power according to the voltage used, using other voltages may cause fire and product damage!