58 MELODIES & 5 VOLUME LEVELS: The doorbell receiver features 58 chimes and 5 adjustable volume levels (0dB-100dB) to suit your needs for different occasions. Easily select from 58 melodies by pressing the Next or Previous button. HIGH-PERFORMANCE TRANSMITTER: Ultra-low power consumption; The doorbell receiver is USB powered, and the button uses a CR2032 lithium battery providing a maximum lifespan of 3 years. IP55 WATERPROOF DOORBELL: The doorbell button housing is specially designed for outdoor use and is suitable for all weather conditions. IP55 dust and water resistance; operates 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 your previous settings; Convenient and easy-to-use design for an enhanced user experience. 200M OPEN RANGE: The wireless doorbell signal easily passes through doors or metal walls, ensuring you never miss a visitor, even if you are a few rooms away or on another floor. Functionality Multiple pairing combinations Configure according to the size of your home environment The number of transmitters and receivers should not exceed 20. 1. Powered by USB and can be placed arbitrarily. Suitable for worldwide use. 2. 4 unique mode functions: flash only (no sound), sound only (no flash), flash and sound, always on and flash. 3. IP55 waterproof button, built-in waterproof rubber strip, truly waterproof. 4. The button adds a cover, which can display house numbers and other reminders. 5. Add front and back door distinction function, press different buttons, the receiver plays different music. 6. The sound quality is crisp and clear without noise, and the sound is pleasing to the ear.