Physen Model CW Waterproof Wireless Doorbell kit with 2 Buttons and 3 Plugin Receivers,1000 feet Long Range,4 Volume Levels and 52 Melodies Chimes,No Battery Required for Receiver 2 remote waterproof push buttons and 3 plugin receivers for you to DIY your house and you can program each push button to a different tone so you can know which door is someone at. Wireless Distance:Operating range from 500 to 1000 ft(1000 ft in open area) for a big house,office, hotel service and other areas that is suitable for short-distance wireless environments Signal Alert:Take care of your family,for the elderly,this doorbell can allow immobile or bedridden patients to conveniently to contact their loved ones when they need help.They can hold on hand or put on the wall for theirs convenience. Receiver Volume:4 levels of adjustable volume from 25-100 dB [much louder].Offer 52 elegant or custom music,from the traditional"Ding Dong" to various well know chimes [more choices] Update:Newest version push button is waterproof/weatherproof,you can install the transmitter outside.CE,FCC,RoHS certified.Here at physen,we encourage you to make use of our One Year Warranty Guarantee. A happy purchasing experience is the utmost importance to us and we will happily send a product replacement if any issues arise.