58 MELODIES andamp 5 VOLUME: Doorbell receiver features 58 chimes and 5 levels of adjustable volume(0 dB to 100 dB) to meet your needs for different occasions. Press the Next or Previous button to easily choose from 58 melodies. HIGH-PERFORMANCE TRANSMITTER: Ultra-low power consumption The doorbell is USB powered, button uses a CR2032 lithium battery that boasts a 3-year maximum lifespan. IP55 WATERPROOF DOORBELL: The housing of the doorbell button is specially designed for outdoor use and is also suitable for all weather conditions. IP55 dustproof and waterproof rating works between -4 F to 140 F withstands various harsh weather conditions. MEMORY FUNCTION: Remembers your last melody and volume level after a power outage no need to reset to your previous settings convenient and easy-to-use design for an enhanced user experience. 200M OPEN AREA RANGE: Wireless doorbell signal can easily cross through metal doors or walls, ensures you will never miss a visitor, even if you are a few rooms away or on another floor. Feature Multiple pairing combinations Configure according to the size of the family environment The number of transmitters and receivers must no more than 20. 1. USB powered and can be placed arbitrarily. Suitable for use all over the world. 2. 4 unique mode functions: only flash but no sound, only sound but no flash, flash and loud, always bright and flash. 3. Button waterproof grade IP55, built-in waterproof rubber strip, truly waterproof. 4. The button adds a label cover, which can place the house number and other reminders. 5. Add the function of distinguishing front and rear doors, press different buttons, the receiver will play different music. 6. The sound quality is crisp and clean, no noise, and the sound is pleasant to the ear.