1000ft /300m WIRELESS RANGE - 1 plug-in receivers included; will not interfere with other wireless equipments in your home or those of your neighbors; ensures that you will never miss any visitors.36 DIFFERENT CHIMES -There are 36 different musical chimes with 4 levels of adjustable volume (High / Medium / Low) from 25-85dB, enjoy pleasant melodies whenever someone rings at your doorEASY INSTALLATION - No batteries required for receiver, just plug the receiver into an electrical outlet. The 12V 23A battery for the transmitter is included. Push button can be fixed to the door-frame with the attached adhesive tapes or using the screws and anchors which are included in the packageLED FLASH ALERT - Blue flash light makes it a more obvious reminder when you are in a noisy environment, ensure timely response even when you are wearing your headphones or even earplugs Also Convenient for the one who has a hearing problemOUTDOOR USE RATED IP44 WEATHERPROOF - Excellent materials keeps itself from getting higher temperature & interference. The push button is rated IP44 and weatherproof for outdoor use,even in a rainy day .working temperature ranges from -4 F-140 F; withstands various harsh weather conditions