Feature:1. Free Installation: Wireless doorbell adopts no installation design, equipped with remote control, easy to use for the elderly, very suitable for the elderly when they live alone.2. 36 Music Selection: Wireless doorbell built in optional 36 different melodic ringtones, allowing you to choose according to your own preferences.3. Long Range Transmission: The wireless doorbell is equipped with powerful wireless signal transmission technology, which can cover a large range in your home.4. Stable Signal: There is a very stable signal connection between the receiver and transmitter, which ensures that you will not miss any important visitors.5. Scalability: The wireless doorbell kit supports the combination of multiple receivers and transmitters to meet your needs of multiple rooms or floors.Specification:Item Type: Wireless DoorbellMaterial: ABSTransmitter: Battery type: Lithium battery, Battery Model: 23A12V, Battery Capacity: 100mAh Number of batteries: 1 (shipped with battery)Receiver: Battery type: Lithium battery Battery model: 1.5VAAA x 2 (shipped without battery).Package List:1 x Transmitter 1 x Receiver 1 x Battery