Aura Systems M3 Waterproof Wireless MP3 Doorbell, Over 50 Chimes, 300 Meter Range, SD Card Compatible Easy to Control: Interface allows you to select from 4 levels of ringtone volume, ranging from 25db to 110db Customizable: Choose from 52 built-in tones, or even have one of your favorite songs play when doorbell is pushed. MP3 function supports TF and SD memory cards Portable Design: Wireless doorbell has an operating range of 280-300 meters, so you'll always hear visitors. Perfect for households, offices, businesses, or even store fronts Extremely Rugged: Transmitter's water resistant and weather proof design is IP44 rated, allowing for both indoor or year round outdoor use Simple Installation: Transmitter can be easily wall mounted through double sided adhesive tape or screw and anchor hardware (recommended)