Flashing color: This product has 7 flashing colors, which can be adjusted according to personal preferences and specific occasions to add decorative effects to the doorbell.Music selection: Built-in multiple music options, users can adjust according to their preferences to create a warm family atmosphere.Wireless design: No complicated wiring is required, the doorbell adopts a wireless design, which is convenient and fast, and no tedious installation steps are required. Suitable for the elderly and the hearing-impaired: The doorbell has a loud volume and is equipped with a light flashing function. The elderly and the hearing-impaired can directly notice the sound and light effects of the doorbell, which is very convenient.Practicality: In addition to being used as a doorbell, this product can also be used as a server for young and elderly people with special needs to call family members or caregivers by pressing a button.Without dry cell batteries: Working voltage: DC4, 5V (3 batteries) Working current: less than 200mA Coding method: power supply Songs: 28 lines Volume: 0dB~85dB [8 levels adjustable)Receiving distance: more than 100M Size: Button 8*5*2.2cm/Part 10.2*6, 7*3.0cm