Newyond Wireless Remote Doorbell with 36 Chimes & LED Indicator (White-Sliver 2) 1 transmitter button triggers (rings) 2 chime units. (Note: The 2 chime units can each be configured to ring with different melodies/ringtones) A perfect use case scenario for this product would be if you have a first floor and basement, garage, or second floor and you want both areas to ring from someone pressing a single transmitter button 36 different ring tones. Operating range of over 500 feet. 5 levels of adjustable volume from 0db to 85db Remote transmitter button is rated IP44 weatherproof and acceptable for outdoor use. Easily plug receiver into an electrical outlet (no batteries required for main receiver). CE, FCC, RoHS certified Package includes: 2 x chime units, 1 x remote transmitter button, 1 x double sided sticker, 2 x screws.