1. High performance: Smart USB Doorbell has ultra-low power consumption, long service life, and a working temperature range of - 20-70 , which can withstand adverse weather conditions. 2. Modern and Practical Design: Our Wireless Doorbell has a fashionable appearance and practical functions. and sensitive, it can be remotely controlled, providing you with quick instructions to that you hear and open the a timely manner. 3. 30 song Ringtones: SOS Button Doorbell has 30 song ringtones to choose from, and you can choose your favorite music. 4. Easy to Install: The Mini Door Bell is easy to install and can be installed in just a few minutes. The receiver can be placed with screws Doorbell Receiver Name: Wireless doorbell receiver Music quantity: 30 pieces Output mode:horn Demodulation method: ASK Control method: equipped with remote control Working voltage: DC5V/1A Doorbell Transmitters Name: Single Button Remote Control Operating frequency: 433MHz Battery type: button battery 2016 * 3 Modulation mode: ASK Encoding format: EV1527 Colour:White Material:ABS Package Contents: 1 x controller 1 x receiver 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.