[No battery required] Using self-generating technology, with the touch of a finger, kinetic energy is converted into electrical energy and wireless signals are instantly transmitted, so you no longer have to worry about changing the battery of the doorbell. It can also reduce battery pollution to the environment. [Long distance, high penetration] The wireless transmission is long, the distance in the open space can reach 150 meters, the coverage is wide, the penetration is strong, and it is stress-free to use through walls. [Multiple types of music] Say goodbye to the "ding-" sound of the traditional doorbell. There are 58 kinds of music to choose from, which are vivid and sweet. There is always one that suits you and creates more joy in your life. [Different ringtones, distinguish different doors] In the multi-drag mode, one doorbell can set different music for different buttons, and different ringtones can be set for the front and rear doors, making it easy to distinguish and not open the wrong door. [Four modes] The doorbell is equipped with a lighting function, which can be triggered by adjusting the switch into 4 modes: only ringing but not lighting, only lighting but not ringing, both ringing and brighting, and no ringing but not lighting. Meet any of your needs. For example, a deaf elderly person can tell whether someone is visiting by turning on a light.[Waterproof and dustproof] Support IP44 level protection. Can be used both indoors and outdoors. [Volume adjustment] 4 levels of volume, freely adjustable. For example, if you have a busy week and want to have an uninterrupted weekend, you can turn the volume down to the lowest level to protect your tranquility. [No -talk] Using intelligent learning code technology, it will not cause -ringing or interfere with neighbor's doorbells when used in any combination. [Intelligent Memory] After a power outage and restarting, the setting memory will be retained without resetting. Type-C input:5V1A Working temperature:-20C-60C Frequency:433.92MHz Distance:150m (in open area) Power:0.5W Working humidity:less than equal 85%RH Volume:0dB-110dB Kind tips: 1. Wireless signals are affected by the environment. The more obstacles, the more serious the signal loss and the shorter the distance. 2. The button cannot be placed on the iron door, otherwise the signal will be blocked. It is recommended to place the button next to the iron door. 3. The receiver cannot be placed next to wireless signal equipment such as microwave ovens and radios to avoid interference with the signal. 4. For outdoor use, it is recommended to use it with a waterproof cover Colour:Black Material:ABS Size:Button size:6.8x4.2x2.5cm, Receiver size:4.2x7.3x2.3cm Package Contents: 1 * Doorbell (Include Chime) 1 * English instruction manual Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.